(You can’t expect to significantly alter and improve a property w/o some reassessment.

@Ramiro RodriguezI use the contract provided by TREC, 1-4 Family Residential contract. https://www.trec.texas.gov/  You may want to consult with an attorney to see if any alterations would be needed to that contract, based on your business model.

Would the fact that dachshunds are generally under 30 pounds alter your take on this--or would a litter of any size dogs be enough for you to say NO WAY?

@D'Andre ByersCircular 26-18-6 - April 5, 2018 - Loans for Alteration and RepairPURPOSE: This circular replaces Chapter 7, Topic 4, Loans for Alteration and Repair, in the Department of Veterans Affairs (VA) Lender's Handbook, 26-7.

There may be ways to alter the allocation based upon common areas such as rooms shared (kitchen, bathrooms, living rooms), a garage restricted to use by one or the other party, etc.You can certainly acquire the replacement property with other individuals. 

Househacking is great for many reasons, but if the goal is cashflow, you need to look in different neighborhoods or alter the strategy. 

If you make the LLC seem like your “alter ego” and not treat and operate like a separate business, you will have pierced your corporate veil.  

Need a contract I can easy alter.

Your tax return/situation is a little more complicated when you aren't doing a single family.From your post, it sounds like you are using the legal entity as your "alter ego" which pierces your corporate veil which loses your asset protection. 

During the pendency and term of this contract, Seller shall not change any existing lease, enter into any new lease or make any substantial alterations or repairs without the consent of the Buyer.