If the savings did not seem sufficient, I might see if his parents could co-sign.

My goal is to pursue the BRRRR model as I want to generate sufficient income from multi-unit homes to allow me to expand my investing business into a full-time affair replacing my current 9 to 5.

However, while the results of your big lift may be lower operating and maintenance costs, if the local market will not support sufficiently high rents to provide a timely pay-back, you have over improved.   

FHA also has a rule called “Net Self Sufficiency” meaning the total mortgage payment must be less than the total rental income on the property.

Once you hold that TIC for a sufficient period of time,  you could sell it to them, and do a 1031 on that sale.

Since he is short on time he is going this route for a few months until he has sufficient time to look around.

However, your landlord is likely notifying you of  the complaint because there are sufficient complaints from her other tenants to warrant letting you know; concerned that other good, quiet tenants may leave if the issue is not resolved; and covering herself in case there is an actual drug issue. 

What I should have done as you rightfully point out is to seek sufficient time to be able to get all necessary bids. 

The fact of you mailing Certified Mail with the RECEIPT is sufficient LEGAL Proof of delivery to the Tenant, and will standup in any JP District in Texas. 

If the partners agree to specially allocate one item (for example, capital gains) 80/20 for economic purposes per SEE safe harbor, the corresponding tax amounts must also be allocated 80/20.However, IRS has a framework that can reallocate the partnership items based on the “ partner's interest in the partnership” if IRS determines the method of sharing the partnership items lacks the “Substantial Economic effect” (SEE) To meet the SEE, there are strict rules to maintain meaningful capital accounts including Deficit Makeup Requirement for those accounts.With the requirement, the partner must at some point contribute sufficient capital to eliminate the deficit, and the partner has the burden of the loss that partnership has and the allocation of the partnership will be respected by the IRS.This is a very high-level summary of the rules and is not comprehensive. there are many exceptions as well.Since the substantial economic effect, safe harbor allocation rules are complex and requires considerable additional recordkeeping, it's easier to follow PIP standard.