A change in life circumstance would have to be the catalyst, it seems 

You'd hate to run out of money because of an unforeseen issue. 

I own a house in Heber, CA, but due to a change in my personal circumstances I will be moving out."

But there could be circumstances where a seasoning of less than (or more than)  one year would be appropriate. 

Hell, in normal times in Kane and Dupage Co it could be 2-6 months since the tenant can come and ask for a continuance to get a lawyer and further delay it at least twice then depending on the next available court date it could be another 45-60 days for that case to come back up in front of the Judge, be glad its not Cook Co it would even be worse because of the sheer size.With all that being said, back to your question - there is no quick and easy way, as much as it sucks that he is now 20 days late in the rent count you blessings that it has not been a year plus that you've had to pay for him to live there, which in many cases has been the circumstances.

I just want to make sure there aren't going to be any hiccups or unforeseen challenges of switching it over to the fixed rate mortgage.

While technically it might be possible to partner with disqualified person under certain circumstances, this is really bad idea as in most cases this would lead to a prohibited transaction and will disqualify the IRA.

I am experiencing similar circumstances in the STL market.

*Please note, there are unique circumstances for each investor.

This might be more of an individual question based on someone’s own circumstances.