Diagnosis: bonnet are some other components are badly corroded and need replaced.

You can't inject yourself into the process of handling any tenant complaints unless the compliant is about rent too high or lease renewal etc...UNLESS you can talk the tenants themselves into performing the physical work necessary for the diagnosis of a problem, while you sit back, cross your arms, sipping on a beer while giving the instructions.

Then using this Info to build a diagnosis and then prescribe an offer.

Diagnosis = analysis paralysis 

You wouldn't go to a divorce lawyer for your Intellectual Property dispute and you wouldn't go to an orthopedic surgeon for your cancer diagnosis.  

He is now considered recovered from autism, the diagnosis has been removed but we're still working through other issues in getting him caught up so to speak.

I don't want to pay for a new unit when its nothing but capacitor or a thermostat, or have a short service life capacitor installed so the Tech can get a quick callback for extra work (not all Techs are top notch in diagnosis).If you intend to learn to service your own A/C units on the fly as they go down, I'd say that's probably a rather big learning curve, and will require some specialized equipment and training on how to safely do it.The rent or buy decision aside, it's best to have a couple of experienced reliable A/C techs at your disposal. 

If the tenant has only been there 2 months and its clogged so dirty that it froze the AC, then something isn't right...... the house/tenant would have to be filthy to do that.You had a Home Warranty company do the work ..... be careful with their diagnosis....those technician are often morons and will do just about anything to not really figure out the issue or really fix it....they do the minimum to appear like they fixed it and move on.....only to have the issue remain and you call them again in 31 days....1 day after the last "fix" warranty is up and you get to pay again.

I hadn't looked into it much before making my post but the cost is $30 to register the pet and then $50 for each sample diagnosis.

@Tom Coakley bring 2-3 waterproofing companies to provide you with a diagnosis of the issue and proposals.