It will be slightly easier to max out your charisma in 0.35 because I decided to make it possible to get it from Samarra even if you choose not to go all the way with her. This should work for existing games too, but I haven't tested it.
Maxing out charisma will be even easier in 0.36 because of Callie's romance path. At that point, there will be one more point of charisma available in the game than you need, which gives you some more choice in how to approach things.
While I can't guarantee it, I expect that Sister Agnes will provide another source of charisma. However, I haven't fleshed out her story enough yet that I know exactly how it will turn out, so things might change.
By the way, you won't be able to get charisma twice from the same source, even in NG+. If you got a point from, say, Nell in NG, she will not give you another point in NG+, even if you seduce her. All your points will have to come from different sources.