Hello!
I’ve never gone to a laundromat in Italy, even though my first hostel in Rome used a laundromat as a check in office. I would always just do it in the sink or shower as I go. One of the other commenters seem to know the topic very well though.
I’m not sure which model of crocs I have, but I think it’s the swift water or something close. I’m eyeing the sexi flip next.
But shopping should be easy. They have chain stores like H&M and local stores too. Last time I had to buy a bikini in Budapest, I went to H&M and spent €30. In the US, you can go to Target, they have inexpensive swimwear.
Here’s my hat: https://www.amazon.com/gp/aw/d/B09SLS5DL3?psc=1&ref=ppx_pop_mob_b_asin_title. There’s a lot of similar generic brands if you want to find an all black one. Mine is the dark grey and though it’s not the most fashionable, I really love it.
And I’ve never flown Ryan Air, unfortunately! But I’ve been looking at their guidelines very close and am trying to whittle my list to fit their weight and size requirements in case I need to. From what I hear online, YMMV but for the most part if it’s on your back and doesn’t look crazy big, they won’t ask you.