I'm pretty sure that there isn't always a villager on the island you visit. I think its random and I'm not sure if the game forces you to save before you visit an island which would affect resetting.
It definitely isn't a 100% guarantee, but its definitely a decent chance. Resetting seems unlikely, due to the fact auto-save exists and I think it saves after you use your ticket.
1. I think the villager changes/is random For every island to visit, or almost every island to visit
2. I don’t think resetting as possible, as new horizons has auto save