I'm into flowers these days too. I like #1 the best, I think it would work better if cropped vertically so as to isolate the main blossom. #2 and #3 need to be shot from a different angle so the blossoms are facing the camera more. I find the back ground in #4 and #5 distracting. (jmho)
Funny thing, I shot the same flowers as 1-3 the other day too and was about to post a thread of them lol

They are Scilla Siberica if anyone is interested.
I agree about #1, def a vertical crop. Your suggestion on 2&3 would be tuff unless you found some on a slope and could shoot up at them , these things are 6ish inches high, the flower is maybe an inch across and often faces down as you can see

. I had my camera just about on the ground to get eye level with them.
I like 2 but the focus seems to have maybe hit the leading edge of the bottom flower, if you hit the focus on the stamen and inside of the petals on the top flower it would have really popped.
I agree again with Greybeard on the last two, pay attention to backgrounds. In the first 3 you have a blue flower against a blue sky which takes away from the flower. I think it should be the only blue thing in the frame
Hope this helps!