Go to Etsy and search for "rental property tracker," and you will find hundreds of nice spreadsheets to track 10-20 rentals, usually for under $10.Software has extremely helpful features like online payments, marketing syndication (click a button, and your property is advertised on multiple sites), electronic document review/signing, maintenance tracking, and owner reports.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

Document the transaction clearly and consult a tax advisor to ensure the structure is compliant and minimizes tax liabilities.4.

Separating Y and taxing it as an S Corp could be beneficial if you're looking to take advantage of those tax savings, but only if Y's profits justify the additional administrative burden.Rental Agreement for Home Office:Yes, you can lease your home office space to your LLCs, but it’s crucial to keep everything documented and ensure the rent charged is fair market value.

When there is a recently acquired long-term rental, lenders can simply throw in the lease agreement and use 75% of the rental income from that, but on a short-term rental, there is no lease agreement, so the only way to document what the actual cash flow is, is by using Schedule E of your most recent tax return filing. 

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

The potential issue is documenting your intent. 

They would need to sign a document for the termination of the town home lease and starting up of the new lease for the other property. 

Unfortunately this is not as apparent and may require speaking with past borrowers but I would go with the lender with a streamlined and rationale draw process even if the underwriting/ origination process requires more of my time & completing/ turning over additional documentation.

Lease should also state that the tenant be in compliant with HOA rules and be provided that document as well to have on hand of the HOA bylaws, rules and regulations, so that if they do have an HOA violation, they be charged that fee and correct the violation [when it's their fault].