I think I just answered my own question, I found this on the wiki page for the AMS compatibility guide, buried down under the legacy AMS compatibility section
X1/P1 Series Printers
Max Connections: Up to 4 AMS (shared limit with AMS 2 Pro/HT).
I’d still love to hear from someone who is actually running an AMS 2 Pro and an AMS HT at the same time on their X1C before spending the $ on the HT.