If you can not wait till tenants move out on their own, allowing you to do electrical during vacancy, I would non renew one tenant at a time to complete the necessary work.

Though I'd rather sell it for a lower price then fix and maintain the HVAC, but a non-working HVAC could deter buyers. 

Once they abate any lead they find, they need to clean the ENTIRE building in order to provide a clean air cert.

I know that on the residential side the process is pretty structured, but how does it work on the commercial step by step before you actually sign a purchase and sale agreement, that is you are expressing your interest to purchase and documenting what you need from the seller but before you make any non-retractable commitment?

Non renewing is so much easier and less expensive than having to evict.

Most lenders I have spoken to require a 25% down-payment for non-owner occupied investment properties.

@Josh Jacobson when you look for financing, there are non-recourse options.

FHA guidelines might allow for your situation, if your a non commissioned W2 employee, self employment or commission in income requires an earnings period to average over.

If using a lender this is a non issue.

Inspect the property prior to offering and lock it up with a non-refundable deposit.