1) first of all, have a good read here, you'll find most of your Visa answers
http://www.border.gov.au/Trav/Visa-1/189-#

2) job hunt is very subjective, maybe some bros here can help

3) again, its subjective, depends on how much is your pay, how much you can save, where you buy, etc...
but if you have been working in both MY and UK, most probably you would already have a house by now... flip it and migrate?

Just my opinion and experience, may differ for other people:

1) Visa and PR is kind of the same thing in a way but to answer your question it is a PR if I understand your intentions which is to stay permanently in Australia. 189 superseded 885 and 175 which were the previous commonly applied visas. This visa lets you stay for 5 years from the date you get granted which at the end you can renew (subject to certain conditions you must meet for renewal).

2) I'm not in your field but not uncommon to hear that sort of story. There are a lot of graduates from all over the world here so you really have to fight tooth and nail for your spot here. However, it's not all doom and gloom as I've seen many had a break through even after as long as 3 years into their field finally if you stick to it. A bit hard to say, I'll leave this to the others who hopefully has had a successful experience with similar circumstances to yourself. I went through the education route so might differ quite a bit.

3) This is based on Melbourne market, you're looking at around 500k-600k for an apartment (2 bedroom) or around 650k-750k for a townhouse so it can vary. You would want to avoid paying LMI which is very costly so this means you're looking at around 80% LVR (in general), base case of 110k for 20% downpayment if you go for 2 bedroom apartment. If you have a partner to help you out it's very doable but will definitely take you at least a few years to prepare especially first home unless you're already sitting on a pile of cash. Alternatively, you can find financiers  who can do up to 90% LVR or buy and rent it out till you are ready to move in (there are tax benefits for this).

Ok, will assist and reply as much as I can:
1) yes it is. U can get 190 too if not enuf points but need to live in that states for 2 years

2) well...very subjective. Some ppl landed with jobs way b4 they step foot here, some 1 to 2 weeks, months or year.
Connection always played major role here with current market. Local experience is the main key too. So try to get into ur profession even though it's small pay or casual. It does helps

3) melb and syd price is pricey but has the higher return investment. Perth 500k can get big house but with low rental income now. Perth is gloomy now....so depends on ur profession demand. If u get a job in perth then it's a good living environment but it's a so called WAIT AWHILE STATES (WA) sloooooooow and steady

I think for 189 also need to remain in Aussie (regardless of state) for up to 2 years for renewal purpose.

- Tax is higher cos u get safety net. Unemployment benefits, aged care pension etc.
If u look at property pricing, i think it is almost 1:1 in dollar terms between KL/Syd/Mel.
Electricity/gas - v subjective. Depends on how much u use heater n how long u shower and which state. WA is more exxy, VIC a bit cheaper. In VIC, elec/gas is $150 a month with little use of heater/gas.
Internet - depends on areas. Some areas unlimited ADSL for $70 per month, others $90.

We usually think the visas (at least for myself) as PR or TR. Do you satisfy the point eligibility for 189?

On your 3rd point, this is based on guesstimates using my own as well, very consistent with what Shazam gave u:

1. Internet - $70 monthly (just taking iinet as an example)
2. Water ($40 monthly on average; just beware that if you are a homeowner it wil be approx $100 monthly because of surcharges)
3. Electricity ($100 monthly average, winter would add anothe $50 assuming you're going to use heater during winter but don't go crazy on this)
4. Gas ($50 monthly average assuming you plan to cook and you use gas stove)

Houses in Melbourne has been rising a lot because of the increasing population and foreign buyers. If you dont mind living further out, you can get cheaper prices than the ones I've quoted. On the plus side, interest rates just dropped recently is expected to dropped furher in the 2nd half of this year. We're currently in a historically low interest rate environment.

I used to engaged with Global Migration Solutions 8 years ago. But my visa type was cancelled by the government and GMS cuci tangan and say not their fault. So all migration fees forfeited.
The agent will only refund you the 'agent fee' if they make a mistake during the application. If your application has a mistake that DIBP cannot accept and reject, your immigration fees will be forfeited.

You can apply on your own without agent. It is abit of a hassle yes. But when you engage an agent, you still have to prepare the documents, contact your ex-company, book your own english exam. What agents do is proof read, make sure your timeline is correct and make you apply properly.

I also engaged with GMS and manage to obtain my PR couple of months ago. Although i engaged with an agent, I still constantly check with them on my status and read up on the rules changes. Cause these agents have plenty of clients so we have to ensure that our applications are moving along and not be left behind.
For me, my skill set was in the consolidated list so i needed a state to sponsor my skill set before being invited to apply for PR once I meet the requirements. I even consulted a second agent opinion early this year as I was unsure if I should renew my documents as they are expiring May 2016. I just didn't want to spend extra money to get my documents renewed as the second agent mentioned that GMS should not even taken up my case as my skill set was not in demand. 
But I was lucky cause at that time NSW was sponsoring ppl with high points, I had 70 points with state sponsor. After that the process went by pretty quickly and smoothly.

Theres been a change in requirements for Skilled Migrations? Meaning by July 2017, those that are able to apply, must quickly apply before they carry out new changes in system after that ?

You are right, which means getting an invitation from government from your EOI before 1st July. So probably best to put your EOI as early as possible.

Quite dependent on how many points you have, the more points you have the faster you get invited and also it's quite dependent on your occupation.

To give you a feel, I applied in mid 2015 with 70 points and was invited within a month.

Submitted EOI back in 2014 with 65 points under 189/190 and was selected for State Sponsorship within a day. Lodged prior to 1st July new financial year. Timeline as follows:

IELTS: 08/03 (exam), 14/03 (passed)
SA: 28/03 (submitted), 10/04 (positive)
EOI: 01/05
SS (akn): 02/05
SS (docs submitted): 08/05
SS (approved): 25/05
Invite: 25/05
PCC: 12/05 (approved)
Medicals: 02/06 (done)
Visa Lodged: 29/06 (Docs front-loaded)
CO Allocation: N/A
Grant: 18/08
1. Unheard of
2. No - it's known as Skilled Migration for a reason. Having studied previously in AUS helps with points, in addition to other factors ie. age, education level etc
3. No
4. Yes

1) Yes I have heard of them. My parents' friends who are Aussie citizens now used their services in 2000. I used Global Migration. I think Worldlink does NZ visas too.

2) No. Does not make a difference for 189/190.

3) No as well.Not unless you're applying for an SOL that is a translator; but this will require proof and relavant assessing bodies to assess your skills and docs.

4) Yes. I had 75 points. They didn't even have to count my Aussie degree and all my working experience; I would've had more then.

3) Yes you will be awarded 5 points if you pass the NATTI translator/ interpreter assessment and got accreditation.

Yea lah bro, that's what I meant by taking a test and having the proper docs to assess.

GM was good, for me anyway. They'll only take you on if they're certain that you'll get. Apparently theire success rate is almost 100%, so they screen you first with a 'free assessment'.

Refund of the visa fee if unsuccessful but not the agency fee. I remember when I signed the first document engaging them. Do read the docs carefully if you do.
If you're taking IELTS, a total score of 8 should be okay to boost your points significantly.