Estimated completion date is November 2021.

She left before final walkout and of course did not leave a forwarding address but I do have her name , SSN and date of birth from her rental application.

After a carefully worded letter explaining that even though there was a moratorium on evictions for non-payment, there was NO moratorium on evictions for Hold Over, which is when a tenant stays past the termination date on their lease.

My question is, is there a way to change the classification from mobile home to a single family home?

Your highest cash flow  and cash on cash return will typically come from a syndication investing in tertiary markets, or niche strategies such as short term rentals and mobile home parks.

Tenant moves out on X date and they pay a set lease break fee.

Ask her to sign a new lease, making the 23rd the new date of paypment and the new beginning of the month.

It is a mobile home that was built onto a permanent foundation with a basement.

Because when you give them the "right" to do so, including a time frame within which the settlement date can be considerably delayed, tenants who actually have zero intention of purchasing can take advantage of the situation and squeeze the seller out of a portion of their sales proceeds through a negotiated waiver or assignment of their "rights". 

You can find out which banks have an appetite for mobile home parks by asking the MH/RV brokers in your area, networking through other owners of parks in your area, or simply obtain list of the smaller banks in your area/region and call them to see if they have lent on parks in the past.