Additionally, we realized the value of collaborating closely with partners to maintain clear communication and a unified vision for the property.

I would suggest to communicate the situation with empathy.

Does anyone have recommendations for an STR on-call service (not full property management), which will handle basic guest communication during their stay and handle organizing repairs (i.e. calling a plumber, HVAC, etc. ... not actually doing repairs themselves)?

Establish a clear process for handling these requests and keep an emergency fund for unexpected repairs.Tenant Relations: Communication is key.

Since your lease doesn't include a break clause, you'll want to communicate openly and give them ample notice, ideally a few months.

- How do you currently handle tasks like maintenance requests, rent collection, and tenant communications?

Anything I need to be particularly cautious of before I communicate this to them?

I will be keeping eye on things to make sure that it gets done, and will stay in communication with his lawyer. 

I ask a few questions such as:-Communication - were they responsive to emails and calls-Property care - any major issues / did they leave the property in good condition-Reason for leaving - this would give you more insight if there were issuesAnd always respect privacy if they are not willing to share.

He came to me by way of my mason, who also uses him.C.S. is really damned good at what he does, and a big part of this is that he's a great communicator.