Evolve finally added my mortgage! New York Community Bank mortgage (mynycb.com) for those interested. When adding payee, it asked me to choose payment address. I found an address that matched, but the name was different (Amtrust instead of NYCB), but I believe it should be fine. I just made a $25 test payment. I'll post here in a few days once it posts to my account.
FYI -- NYCB helpfully has this info from their FAQ:
What happens if I mail a short payment?
The payment must be equal to or greater than the payment due or it will not be posted to your account. It will go to a suspense account and will not advance the due date until additional funds to total a full payment are received. If the difference due is not received before the end of your grace period, late fees may be charged.
How is my monthly payment applied if I send in extra principal?
Before payments can be applied to principal, you must bring your account current by paying off any outstanding fees and late charges. Extra payments will then be applied to outstanding principal.
Now if only they would add PenFed (penfed.org) and UFCU (ufcu.org) auto loans....