1.) I think @mainline meant 2.4.2. It is already released, but we are still dealing with some problems:
.) Great buildings is still not working
.) Events only work on German servers. The problem here is different time formats.
The Investments should already be working under Statistics => Investments
2.) Yes Date on investments is already planned, but I cant tell you when it will be released yet.
3.) It is impossible to calculate if a place in a GB is locked without opening every GB first, because the overview does not contain the rankings, but in the ingame sum there is already a rough filter:
.) If there is more FP left than your investment, the place can not be locked. In this case the reward is capped at your investment. So if you place 1 FP in a GB I will count only that one FP and profit is 0.