The rear shifting has nothing to do with the compact. As for the chain length, if it's set it to the maximum length in the little/little, you have the maximum chain wrap. Chain length will not affect shifting precision either. If it doesn't hang loose or rub the RD cage in the little/little, it is not too long. If it wraps the big/big it's not too short.

The lack of (easily used) FD trim is a shortcoming of Shimano shifters. With Campy, you have four clicks that put the FD wherever you need it. The clicks are all the same - no soft or partial clicks for trimming only. It's normal to trim the cage to the right when you get into the smallest four cogs. I always use the FD that matches my Campy 10 or 11 drivetrains, but the 10 speed will also work fine with 11. The slightly wider 10 speed cage does not eliminate the need to trim from the little ring.