Any thoughts or ideas on what to look for during this process?

Look into what type of insurrance you need first.

I live in Orlando and have access to many dancers and theatrical performers. That being said I have used as my main assistant a girl named Ute from Germany.since 1996. I have paid her extremely well for practices and performances. She is a trained ballet dancer and they are the best. Next, would be ballroom dancers. Be prepared to spend a significant amount on custom made costumes.
Also, get ready for fellow magicians to try to hire her and “just use Kendrix’s choreography “.

THIS …. is absolutely the hardest part of performing illusions

My advice is to view her/them as a co-star not just an assistant. Good pay, insurance, paid training, and on operations, both business, performance and related. If possible try to find someone that is used to working as part of a team, group, or troupe that understands industry operations and expectations. Gymnast, acrobats, theater, and trained dancers. Make sure they have a proper and accurate description of the position not just in performance but in all aspects of pre and post operations.

Know what duties you expect from them besides the performance - merch/BOR, setup/breakdown, press and media, driving, promotion, teasers, etc.

Best of luck!