Being new to all of this I am having trouble determining what percentages to use for  Maintenance & Repair/CapEx to arrive at a monthly cash flow figure?

WIth that comparable, you can arrive at a fair price for your house.

We are arriving at the same figure.

I'm planning on asking for a letter of intent from his employer to confirm that he will have income when he arrives. 

My "rule of thumb" is that if you can't get (at least) 1% gross rent per month out of its value (in this case, that would be $4,000/m), you'll arrive at the very same question you're asking!

but am looking to make the transition to staying home once baby #2 arrives.

Here are some of my random thoughts on this.You want subs who's work is constantly done in a “workmanlike manner”, who will show up when scheduled and finish on time and on budget.When you are running a job, it's important that Trade A complete his work (ie Electrician) before Trade B (Drywall crew) arrives a week later, because if that doesn't happen you lose control of time, and time is money (Unforeseen construction delays and cost over runs can throw a project into bankruptcy).This requires good subs, and if they don't pull the load with this, replace them quickly.Learn how lien releases work in your locality (it's different all over), get lien releases when you give a check...no lien releases, no check.

They ask for a plumber because the "Toilets have been clogged since they arrived" (one of many lies) and I send out my plumber.

I'm also driving to an area of interest (CO Springs) in a few weeks so I'll reach out to local agents to start the dialogue before I arrive.  

I am greatly perplexed at where they may be getting this info from and how they arrive at this pricing.