Could somebody please explain to me the difference between.....

Sure Tour Championship winner is winner using handicap start and lowest 72 hole score is as you say without handicap. No trophy and no title for lowest 72 hole
score but OWGR points will be based on actual score.

Thanks very much !

could someone explain the difference between the fed ex cup winner and tour championship winner markets?

No difference but Fed ex cup winner market been in existence long time.Tour championship winner market only just formed.

thought as much. The old fed ex cup format and winners market used to be a little goldmine

It makes you wonder why form a Tour championship winner market at all.  Can't be good for liquidity can it?

Not exactly the same-----Tour championship is N/R no bet.