I don't know if I can find the full photos for these but I can tell the date of it, easily.
First photo: assumingly at 1977 Second photo: late 1981 – 1982 Agnetha Third photo: Frida and Agnetha together in early 1980 before she went 'Super Trouper'. Fourth photo: Something from 1979. The red flares were definitely 1970s, but yep, that's a harder one... without the obvious details like the Napoleon bust.
2 and 3 are on the right track.
Meanwhile, I have stupidly forgotten where I got 4 from.