If you're never going to stress the Mini2, and will only do modest games, email, web browsing, video viewing, it will be fine for now, though iOS 11 may be uncertain. As mentioned the Mini4 (and Mini5 even more so) is more future-proofed. One thing I don't believe was mentioned is that the Mini4 has TouchID and the 2 doesn't. That may not matter to you of course, but I like it. I had a Mini2 and traded it in for the 4, and never regretted the trade.
I have a Mini4 now and am happy with it, though don't find the Air2 that much harder to carry on trips, so I don't use the MIni 4 for very much. If I had it to do over, I think I'd have skipped the Minis entirely, though I do like it for reading or video-viewing in bed (light weight much easier when laying on my back). But for other purposes, I like the size of the Air better and don't find the size a problem.