Do you have to used tinned wire? No.
Is it a very good idea to sue tinned wire? Yes!
Do you need to use heat shrink connectors? No.
Is it a very good idea? Yes!
Do you need to use dialectric grease? No.
Is it a good idea? Not with adhesive lined heat shrink connectors!
Proper crimping is critical to the entire system.
This will give you some more info.
Crimping Marine Terminations (LINK)
Also here is a great on-line wire gauge calculator:
Wire Gauge Calculator (LINK)
Also please don't buy wire from any of the big chandleries as most have been suckered into the Ancor scam.
Here are two exceptional sources for both wire and crimp connectors.
Sailors Solutions - Berkshire Wire
Sailors Solutions - FTZ Crimp Connectors
Sailors Solutions - Heat Shrink Crimper $39.95
or
Genuinedealz.com
These guys offer free shipping within the US..