You are not scrambling to get 4 units filled at the same time  You can definitely ask for it to be vacant but it will depend on what the lease say.

What about one that is just too far away (depending on your geographic preference - some dont care about "clustering")?  

Can these be tax write offs (home office, phone, car expenses, etc) even though I won't technically be making money for some time until everything is completely built and leased?

Ensure that she has renters insurance in the event that she floods or burns her place down - depending on how attached she is to her belongings she may seek reimbursement from someone (probably you).

.- Tax Benefits: building deprecation, cost segregation, write offs etc..- Principal debt paydown: tenant paying off your loan.- Cash flow.Once the above are all added up, your true Rate Return will by far exceed your returns with stocks.Now regarding the different type of real estate, that depends on a lot of factors and mostly on your financial goals and where are you in life today.

Make sure your lending is solid and you submit a pre-approval letter with the offer this will help the seller know you have the money to close.  

Assuming #2, and rental income of $50k/mo (ex. 25 units @ $2000), how much would we reasonably expect to take home (Net rental income not counting taxes)?

We replaced the A/C unit 2 years after and that was also depreciated. these are part of gray area, it really depends on context when you need to do something.eventually one tax expert would not agree but i personally okay to be challenged in audit for this.

Locating properties has been the tricky part for us to navigate (tax deeds, auctions, foreclosures, reliable wholesalers, vacant properties, etc).3) As we embark on this journey, we are also looking for mentors who can guide us through the complexities of property investment deals. 

ISO company that does creative HELOC's:I have a find with great equity in his home but not great taxable income. Are there companies out there that would give him a small loan?Best,Alex