Really cool! Nice to meet you, please do get involved! My estimate is more in the range of 10-15 people working on Cashu projects, some more some less! We are still early and we plan to upgrade the protocol this year but we'll try to keep it backwards compatible for the time being. If you use libraries, you might not even notice but we will see!

Make sure to join our dev chat and say hi! https://t.me/CashuBTC