Would you recommend we begin interviewing architects once our offer is accepted? 

The Tenant has to sign it and accept the charges or they can refuse to sign and take you to court to contest the charges.Unfortunately, your friend did not create a list so you will have to refund the deposit and eat the loss.

Every investor has their own list of criteria and idea of acceptable amount of risk per return.

From the seller, definitely get history, insurance, tax info, any planned special assessments, major repairs, any warranties (foundation, waterproofing, roofing, etc), a copy of all leases to review as part of a formal accepted offer, etc. 

According to the cdc, the minimum distance acceptable between a water well and a septic system is 50 feet.

This question brought about an interesting find in a website called Neighborhoodscout.com. 

Hey guys- I placed my (tenant occupied) Austin house on the market yesterday and our showings have been positive– received an offer earlier this morning that I think we will end up accepting.  

This gives you a sf/person number.Supply and demand equilibrium is generally accepted as 8 feet per person.

Let the seller decide if they are willing to accept it.

Here on BP is a good way to do that but other websites too.