I agree that Ideologies are a compelling and well-balanced part of the game. At Deity, my play is too weak to win with anything but full Tradition plus full Rationalism. But I have used all three Ideologies to good effect -- including SV with Autocracy and diplo with Order. I actually think Freedom is the most balanced, but also the weakest. Yes, slightly less happiness, and most of the Level 1 tenants are weak. Freedom has three decent tenants for war mongering, just nothing courthouse-wise.
maybe try tradition + aesthetics, you can pick up secularism, but I don't think other things are that critical towards CV. freedom isn't weak imo, even in the early tenets.
avant garde is equal to hero of the people, and food from specialists is around +5 food for each city. The main thing I think is great about freedom is that you can pick tenets that synergize with SoL so well.