Part of the problem is that you want to record things that aren't the most typical for recordists on this board, so we might not know what works best in those applications. And part of the problem is you want to record different types of things, which might not lend themselves to the same types of mics.
For recording environmental sounds, I'd think that you want to use omnis based on their characteristics (though I haven't done this type of recording). For recording amatuer musicians in your living room, I think either omni or cards would work. Personally, I find cards to be a more all-round mic to use and I'd tend towards them for this application, using a nice stereo pattern (ortf, din, etc). I wouldn't worry about the loss of bass at a distance, this won't be that significant and you won't be that far away.
For doing interviews, I have no idea since I don't know exactly how or where you are recording these. Off hand, I'd guess that the directionality of cards could be very useful in conducting interviews, and might help keep down the extraneous ambient sounds you're not interested in, which you'd pick up more of if you use omnis. Also, again, I don't think the larger distance rolloff of low frequencies DPA spoke of would be an issue here. Probably the opposite, to the extent cards roll off low frequencies, it would work to your advantage. Spoken voice isn't going to be using these frequencies, so if you roll off low frequencies with cards compared to omnis for interviews, you'll probably be losing unwanted HVAC noise, trucks rumbling in the background, etc -- all sounds you don't want to capture anyway.
Bottom line, I'd still recommend using cardioid mics as a good all-round choice. You might want to see if there are any ENG discussion boards though to ask around in, as I don't think interviews and ENG is a very big topic on this board.
Good luck!