How successful are multiple island trips for villager searching?

[jiojiop]

If you have an open plot then there will be an animal on the island, no?

I've yet to find an empty island from my 400+ trips as long as I had an open plot available.

Will you get a random move-in the next day if you don't invite someone the day you build the empty plot?

 

[brockbrock]

Will you get a random move-in the next day if you don't invite someone the day you build the empty plot?

Not necessarily the next day. It could take a few, but I would advise it's not worth the risk if you are not wanting to roll the dice with a random villager.