Sorry for missing your reply here - it might be better to post a new thread to make sure it doesn’t get overlooked.
E-mails should be lowercase and remove trailing and leading spaces, then SHA256 without a salt. You can find example for hashing here: https://github.com/twitterdev/ton-upload/blob/master/ton_upload or https://github.com/twitterdev/ads-platform-tools/blob/master/python/hash_tailored_audience_file.py
The audiences require a minimum size of active users to be able to be used in targeting campaigns. I would recommend using a larger e-mail data set to test with or handles. You can also try the upload with ton_upload above and compare result, you should be able to get to the same result with the memberships API.
Please go ahead and post a new thread if you are still having issues after this debugging!
