The more they move in the longer they stay--- you never know what their needs are going to be.

The people you are going to for capital have it for a reason....

from a laptop or mobile phone on one of my SFR's (internet must be hooked up, but most tenants do it anyway and like to be able to monitor the outside of the house remotely, even if there's nothing going on.)

I would look at the DSCR loan as the first option.By the way, I suspect you are going to be disappointed by any refi appraisals   ADUs typically appraise poorly   JADUs can lower the property value Vs having the space as part of the primary unit.  

Would it be frowned upon to use a seperate personal account strictly for the business until I get back to the states in about 6 months to phyiscally go and open a business checking account.

It's easy to obtain, costs very little, and doesn't require extra, on-going effort to maintain. 

in a stick frame market and one of the cheapest markets to build we build with margin at $190 or so a square foot. that will go up over time about 5% or 10% a year to keep up with new build price increases. we are buidling a 3 story walk up and source some of the lowest priced crews.

Many investors share opportunities, tips, and advice in these groups, which could lead to mentorship connections.Shadowing tips.

Any semi-intelligent agent is going to do the math and want to cover their expenses.

Typically companies like this actually want stuff like this reported so they can see if its a bug or what is going on with their system.