I have a separate heating thermostat and cooling thermostat can I combine the two into one and I also want to have the heating unit fan turn on when the cooling unit turns on because I am using the same ductwork for both and the extra fan from the furnace will help the ac unit move the air better

So you have 2 separate systems? Might be difficult to do with a setup like that since you also have 2 control panels. You could try to move the heating stat to fan on with the heat off and see if that helps. .