You could do a reno to your unit as extensive as a full remodel, or just a roof, HVAC system, and/or upgraded electrical service (you get to add it to the reno because it affects your 1 unit but it is great because that infrastructure improvement benefits the other units incidentally).

I have several deals on my plate with similar numbers, and expect to find myself in a similar situation repeatedly. 

Rinse and Repeat!!  

My question is;  how important is the repeat part of BRRRR to scale quickly? 

But all my repeat clients are very happy with the work we do, and at the price we do it. 

Your construction is going to affect the peaceful enjoyment of the property; something every tenant deserves.

Will that affect my chances of getting the loan and if so how can I get around that?

Each question or scenario will be case by case and directly affected by which strategy you choose to deploy. 

If I have all of my properties with one insurance company, can a claim on one property affect my other properties?

I don't think this will affect prices in the city but it should help drive rental prices in some of these sub markets.