Intel Core i7 6700 - RM 1295
Gigabyte H170M-D3H - RM 469
GSKill Aegis 16GB (8GB x 2) DDR4 2133MHz RAM - RM 338
EVGA GTX1080 8GB GDDR5X Gaming ACX 3.0 - RM 3199
Samsung 850 EVO 250GB SSD - RM 469
WD Blue 1TB HDD - RM 219
Superflower Leadex Gold 550W - RM 409
Corsair Carbide Air 240 - RM 455

Total: RM 6853 (Idealtech price inclusive of GST)

To lower down the total cost, you can do the following:
1. Get a cheaper and smaller size SSD (or remove it completely if you don't need it)
2. Get a cheaper PSU (full modular is recommended for cable management purpose)
3. Get a cheaper GTX1080 like Palit Jetstream which runs at stock reference clock speed (you can overclock manually if needed)
4. Get a cheaper mATX case

I don't have any hardware price list from Yik Foong Complex & Perak IT Mall (if you want to get it there then I cannot help with the price) 
Intel Core i7 6700 - RM 1289
ASRock H110M-ITX - RM 315
Corsair 16GB (8GB x 2) DDR4 2133MHz Value RAM - RM 312
Palit GTX750Ti 2GB GDDR5 StormX OC - RM 488
WD Blue 1TB HDD - RM 209
Corsair VS450 - RM 162
CM Elite 110 - RM 159

Total: RM 2934 (ETech price inclusive of GST)

The dedicated GPU included is only useful if you enable GPU acceleration in Premier Pro, you can remove it if video editing is not the main priority, SSD addition will boost the speed of the rig in terms of overall system responsiveness and shorter boot time.

If you need the rig to be even smaller, you can consider other chassis like RVZ02/01 (console alike).
Not recommended to pair i3 with GTX1060, some (not all) CPU demanding games will show bottleneck (GPU can't fully unleash its power due to slow CPU).

1. It will work.

2. Yes.
Exhaust on top.