Ryan,
A few Questions:
-Are the properties vacant? The only reason I can see not letting you in is if they have tenants. Otherwise, beware.
-If there are tenants, what are the lease terms and rental history (are they current)?
-Has the seller given you a property disclosure for each house? If they use a Realtor, they'll have to do that. Asking for one may give you some insight to the condition inside.
-What's the empty lot going to provide you from a value prospective?
-is your rehab budget per house or all in?
-How's the neighborhood? Good rents? Desirable location?
-If you buy the deal, how are you going to finance the BRRR? An empty lot is harder to finance than a house so you may have to plan on owning it cash. It may not make sense to get a 50% LTV on an $18k lot.
-How are you paying in this BRRR? Cash in and refi later? If so, run those numbers on the holding costs until you can get the refi done.
If this were my potential deal, I'd start bay running the numbers on the rent as you plan to BRRR these. Also, find the value of the Lot to you or someone else. Unless you're going to develop it, it sounds like it's not worth buying unless it has to come in the package.
The newer roof and new A/C unit says to me that (at some level) maintenance is or has been performed. That's a good sign. The 6% commission is worth $12,900. My top price (assuming the cash flow numbers work for rental) would be $200k no matter what. That's saving the seller commission and the hassle of showing it, dealing with the tenants (I'm assuming there are tenants).
The rest of your math looks correct (assuming all in at $30k for both houses). I'd imagine that your rehab budget would be shaved down a bit per unit if you do both at once. You'll be able to negotiate a better deal if you're giving a contractor 2 homes side by side to do the exact same finishes on. (same toilets, sinks, carpet, tile, paint, etc.)
I'd ask the seller why they are selling. Repeat their answer to them and ask another Why question, repeat one more time. This may get you to the real reason they are selling. For example;
Me: 'Hey Ryan, why are you selling these houses?' You: 'Well, we're just simplifying things..' Me: 'Oh, great! I'd love to help you with that, what's your biggest challenge with these homes, what can I do to help you simplify?' You; 'We are just looking to get cash out (or get out of landlording/or we have bad tenants/etc)" Me: "great, what do you need to get for these homes to help me wrap this deal up for you?'
I find that some just need/want $$$, some want our of being landlords, some have major home issues that they don't want to share.
Best of luck with this deal!!