The limiting factor is speed/time since you can only do one at a time.

We will have one time charges too as we need to keep shared utilities in our name even though tenants will be responsible, so that another factor I like with Cozy.

no.Look at the income, find out what cap factor is appropriate for the property, get value from that.If the building is 4 units or less, use ANY 4 unit or less building to compare and scale the number by number of apartments.If the building is 5 or above use any 5+ sales and scale the same way.You could also look at existing properties that are for sale and calculate their cap rate to judge where you should be.

Particularly if Tesla moves forward with their huge factory investment that is proposed to bring 5,000 jobs to the area.

Setup alerts that e-mail you news articles identifying when and where large employers are adding factories/plants/jobs (I receive these daily). 

Some items are a static cost that don't change, but in a renovation like you describe, the big factor is going to be labor and material cost. 

One key factor is you need a good support system back home.

This approach has I believe resulted in long-term tenancy and low-turnover is another key success factor. I

In the passed 2 years I've been watching my credit score like crazy, going from nothing to a 750 (fico 8) with only credit age being a hurting factor. I

Another factor is that it's in a not so great neighborhood, but that has signs of revitalization going on.