You can't either. You could only watch it from HyppTV everywhere on your mobile device

As I know you cant do that 

That was the past promotion, got new one with webe or voice call plan 20 or none.

Yes this is the new one, discount rm 20 for your internet if take webe 79.

There is an option for you to add hypp tv subscription to unifi lite subscriptions,  but its rm30/month. So not worth it, might as well upgrade the package.

Let's me explain pricing for UniFi Lite

First, you need to understand that any UniFi package must be bundled with at least 1 HyppTV Pack worth RM30 except if it is bundled with WeBe.

UniFi Lite base price = RM 99
1 HyppTV Pack =  RM30
1 Voice STD 20 Call Plan = RM20
1 Webe Call Plan = RM79

The minimum combo is

1.UniFi Lite + 1 HyppTV Pack = RM99 + RM30 = RM129

Another combo can be

2.UniFi Lite + 1 HyppTV Pack + 1 Voice STD 20 Call Plan = RM 99 + RM 30 + RM 20 = RM149

3.UniFi Lite + 1 Webe = RM 99 + RM 79  = RM 178

Normally TM will give RM20-RM30 discounts for each promo based on past promotion.

There are no such things as

1.UniFi Lite without HyppTV Pack
2.UniFi Lite without HyppTV Pack with call plan
3.UniFi Lite without HyppTV Pack with free call plan

*All price is excluded GST

can if the current number is from the same exchange as your UniFi.
Nop, direct downgrade is impossible.You need to terminate your current one and get a new one.The termination fee is applicable.
HyppTV Pack is always there for any UniFi package.The only difference is that you don't get HyppTV STB when subscribing UniFi Lite 10Mbps.Need to use apps to watch.

Unifi at your area is VDSL2 (FTTC) or FTTH?
If VDSL2 (Copper), you need to terminate your Streamyx to give way to Unifi VDSL2.
If FTTH (Fibre), then ask for migrate to Unifi, TM will install a new cable from DP to your house. You should be prepared to pay for some installation cost (eg wiring inside ceiling).

Previously I am using Streamyx 1 Malaysia Broadband package 4mbps RM88.

When moving to Penang from Perlis, TM told my that there are no port of 4Mbps streamyx at my new residential area (Bandar Tasek Mutiara, Simpang Ampat). TMpoint CS at Kangar told me that I need to upgrade to unifi. At that time i think this is their strategy to charge me more from RM88 per month to RM179 per month (I am not willing to terminate that RM88 4 Mbps package yet). So due to no port available TM downgrade my streamyx to 1mbps. Before they manage to install streamyx at Penang. I walked in to TMPoint Kulim and asking about the available streamyx port. Same answer given.

Luckily the CS told me they have new offer of Unifi Lite RM129 (without free call 600 minutes) instead of RM149. So I registered for this Unifi Lite and the Streamyx is terminated without any penalty.