What are the best orange hero's to have and how to place them in the APC's with what type of troops?

For orange heroes the S (season) heroes (S1, S2 etc) are potentially the strongest, however to make them strong you have to unlock their skills and this takes duplicate heroes (for hero medals) and it can be very hard to get these, unless you play a lot or pay money.

The best orange heroes without spending a lot are the ones that you can get and unlock the skills for. Always check through the skills list though to see if they are specialised for a particular troop type (ie some skill only work when leading fighters to vehicles etc.)

For troops you should try to match troops to heroes if the heroes you have are specialised for them. Otherwise just use whichever you prefer and that match the needs. Fighters have high destructive power. Vehicles are fastest. A mix will work well in most circumstances but having all one troop type in an APC can give good buffs if you have the war room buildings unlocked and upgraded or the right parts crafted and applied.