Although many FF programs allow you to get flight credit in their own programs for flights flown before joining their FF program, most FF program Ts&Cs I have seen do not allow you to obtain partner credit retroactive to your joining their program. (I admittedly have not checked the FF program Ts&Cs for the airlines you listed.)

So second-to-worst case, it may be you have to open an FF account with each of them in order to get credited retroactively.

Worst case is you don't bother opening a boatload of new accounts and just don't get credit, but learn from the experience so you can improve your earning opportunities in the future.