The con is obviously the cost because in addition to waiting a long time for permit, it requires serious structural changes + roofing, etc. 

Should I wait until I’ve purchased the property, or start once I’ve decided on the target market and city?

Avoid templates at all costs, especially with laying the foundation for your business.

Some states allow an eviction for repeated violations of a rental agreement.It is also not a good practice to wait to long to raise rent to market rates. 

It took 9 months from front to back with was too much time, but the wait was worth it.What made you interested in investing in this type of deal?

No one can 100% answer you what you can do here.The one general question I would give my opinion on is if the resident is responsible to pay for the damages, do no wait to use the security deposit.

Waiting until market downturns might limit access to capital.

Are they laying out things down to your kitchen cabinet sizing?  

. --- If you close on the property in November and immediately send the 30-Day, you LEGALLY have to wait until January 1 to file a landlord-tenant case to regain possession is the tenants have not vacated.4) Your rent losses will be November, December, January, February and probably March if the tenants choose not to pay and you have to evict.--- Make sure seller at least collects & prorates November rent to you!

I would ask Stessa directly for help but their business model seems to be to advertise "Priority Phone Support" but force you to wait 2 month to make a phone appointment. thanks in advance