Your answer can be found here.

Hi all, recently just opened a singapore CIMB fastsaver account and it took me less than a week to get it fully activated, so I decided to write a guide here for all the new people. It took me a total 4 days to fully activate the account.

Day 1
1. You must have a cimb malaysia account first.
2. Head to singapore cimb fastsaver page and fill up the registration form
3. After filling up the form, you will get an email and sms instantly. (you will get your fastsaver account number)
4. login to your cimbclick malaysia. Go setting and link your cimb malaysia to the cimb singapore. 

Day 2
1. Successfully linked my cimb malaysia to cimb singapore account
2. transfer 1sgd from the cimb malaysia to your fastsaver for KYC process
3. Ask my friend from singapore to transfer 1000sgd to my fastsaver account (Save money without using cimb forex rate because the spread is too high) (and my friend wanted to transfer sgd to myr, so we do it without crossing the border)
4. lazy to wait for the call from cimb singapore, so i head to their website and filled up the enquiry form asking general questions and what to do for next steps. (obviously im just fishing for them to call me asap)

day 3
1. cimb singapore called me for verification process. reason i say i want to invest in singapore.
2. they say ok, will pass the application to another department and i am subject to their approval.

day 4.
1. finally received email and sms for my account activation.
2. you will get a code to sign up for cimb click singapore
3. go sign up for singapore cimblcick and done.

The process is very smooth. And it only takes 4 days from application. They dont even ask for my net worth etc. I am unemployed lol.

Just use Cimb MY to trasnfer first time.
If you withdraw back to malaysia you are just inuring extra forex loss for yourself.
Can withdraw. But the question is where are you going to put it?
You can leave like sgd10 inisde. I have never leave sgd 0 inside cause I don't want them to close my account. Keep in mind if lots of people does that sooner or later cimb going to implement fall below price. So pandai-pandai.

yup. at least sgd 1 from ur own account. the rest can be from other sources. this is according to someone who recently opened an account.