ThankYou point transfer partners are summarized in the Wikipost at the top of this thread:
https://www.flyertalk.com/forum/citi...-partners.html
Citi uses Connexions rather than Expedia to operate their travel portal, but Connexions often outsources hotel bookings to Expedia. In general, if you redeem points (any points, American Express, Chase, Citi, Capital One) the airline tickets are normal mileage earning fares, but chain hotel stays are excluded from earning rewards and benefits. There are exceptions. The best place to research hotel policies regarding travel agency bookings is in the individual hotel forums.
How about directly booking on TY web site for a travel (instead of transferring to an airline)?