I have used the Pella for a very expensive project and love them but don’t have the budget to do them in a medium-priced rehab.

Remove the time and budget risk of a full rehab.

CONS: HOA fees can be hefty, you can be individually assessed if there is a large repair in the complex and they don't have the money in the budget to repair. 

So I have a few questions;- Should I entertain exceptions, a 'pets on approval' policy - based on breed, behavior, etc?

You can do it on a budget, too.

My area it is $6 sf to replace. 2000 sf*$6 sf=$12000/10 year life span/12 months in a year=$100 per month. 1 item already exceeds your capex budget.

. ;-)As entertaining as HGTV is, it is not how real life operates.

This is all not taking into account the fact the city of Baltimore will face a huge budget shortfall, which will lead to more problems in solving basic city problems.

Do you guys tend to split the down payment and rehab budget 50/50?

For example, if you only planned to have the unsecured loan for a month or two, but the seasoning requirement is 6 months, you'll want to budget for the higher interest/payments for those additional months.