New to the Khadas but have a RPI3 b. My question is will the power supply for the pi be ok on the Khadas?
Yep, but spec with 5V 2000mA+ is recommended for VIM2.
I also came from a Pi3 - same caveats apply with VIM2 to use a decent PSU and cable. In fact with VIM2 the cable comes in the box which is handy as you need USB-C.
My first boot was a poor experience (self inflicted) as I plugged the other end of the Khadas cable into a USB extender I have: Android came up fine but as soon as I tried to set the WiFi connection the VIM2 shut down. Turns out my USB extender cable is poor - since I plugged directly into the wall-wart have had no problems. Note the official Pi3 PSU I have from CPC (Premier Farnell) is NOT useful as it is hard wired to a micro-USB connector - the VIM2 needs USB-C.
Thanks for the advice I will take a look round for a suitable ps and fan & heatsink also