Will there be more rounds of items added to Esther's shop like there is in Masquerade? It's been forever since my last Vesnali and I can't remember.

I can't say for sure but I don't think so. Vesnali only lasts for a week

In the news post for the 1st day, Amber posts that this is the only wave. There will be other Vesnali type items released other ways but not in the shop.