I can’t speak to travelling to other islands, which skimming your post is what you seem to be talking about. I was referring to Armando’s thought that the random pulls coming from tickets are different each time. She only sells you one Wallpaper (with 5 tickets) and then if you bring another 5 tickets to her, the only option she gives is to buy the Flooring (or vice verse). If you travel to another island after buying up her inventory of 3 unique rugs, 2 wallpapers (one random, one with tickets), and 2 flooring (one random, one with tickets) I can’t speak to what happens, I’ve never done it.
EDIT: I suppose it’s possible if you got a third set of 5 tickets, she might start offering all new flooring or wallaper, but I strongly doubt it. More likely, she would tell you she doesn’t have more to give for tickets and you would save them for next time.