They charge 10% or a minimum of $75 per property.

Instead, the full amount of the property tax is calculated at the applicable rate, then the amount of that tax attributed to the school tax is subtracted from the final property tax bill for owner occupants. 

So I have a townhouse that just went vacant due to the tenant buying her own home in the same community and we have a few applications in in less than a month for new tenants.

And now refuses to pay the $100 application fee( $50 per app, 2 applications).

This is in addition to all the other expenses you'd find in a condo HOA or common charges.

I wanted to sign them both up for a 12 month lease, so that even if one of them leaves, they are both still responsible for payment.Should I ask them to apply as primary, and co-applicants?

If they do terminate the lease, be sure you're given proper notice per lease (read it) and applicable laws. 

Unfortunately I don’t think I can charge enough rent for it to cash flow.

I spoke with an attorney and wow, they want to charge me over $700 to file 2 forms...it looks like one is a new deed. it basically says she is selling (no money) her portion to her and I .

On the same project I've received quotes that were over 150% higher than what my current installer charges.