So, typing A with a weak pinky finger is not a problem? Don't you see a contradiction here? IMO this is an advantage of Colemak's design that it gave a chore duty for pinkies that does not require them to jump around but still use them regularly and unload other fingers this way. Typing rolls pinky-to-index or other way is also quite easy and gives more good rolls in the layout.
Just for comparison, Russian national layout put A and O at the index fingers homing positions, and most frequent consonants around them, and here we go, it is not so unusual to have 3-4-5 same index finger combos there! And that layout does not use pinkies for any serious job, so users truly believe that that is for good, because pinkies are weak (and their pinkies are really weak, they never trained them!).
I do not quite get what is the issue with U though.

Poetically, "From A to O" means "everything" since Omega is the last letter of the Greek alphabet. Isn't it beautiful then that Colemak encompasses everything within the boundaries of your hands in this way? ;-)

You can, while for me I think it feels okay. But yeah, I see what you mean. If it really bothers you and you don't want to train Pinky Fu too hard, I'd consider using alt-fingering for that word. One suggestion is to slide your hand one key to the right and use the 3-4-2 fingering instead of 4-5-3. With a little training and a not too heavy wrist you can slide like that almost effortlessly.

Pinkies up, Spongebob.