1. Reviews are not comments, and index are set up to comments. I think this is the reason the Revelanssi are not indexed in reviews session.
2. Yes, I am talking about dropdown search. The search engine is directly from Porto Theme.
For example, for words indexed from title or product text, the drop-down search are working perfectly. And our search engine naturally can index just titles, this mean for product text descriptions the search engine are using Relevanssi index.