I don't think Idol ES is going to succeed. Frankly, I'll be surprised if it ever gets off the ground. If it does, I could see Nijisanji trying to copy it, and failing miserably just like they have with every other overseas Nijisanji branch.
Hololive doesn't need to copy less successful vtuber companies, so I don't think we'll see a Hololive ES branch. We might get some more bilingual Spanish speakers in the EN branches though.