Assuming rents rise over the years and I make continual improvements to the place, I would be set up to transition into the traditional hacking model of renting one unit in whole and occupying the other side myself. 

Traditional Financing How did you add value to the deal?

We also do traditional residential real estate investment as well.Cool project in a pretty area!

Is it possible for a more traditional investor (someone not using brrr) to finance their way to 100 units?

There are many building materials that are becoming more popular as the price of traditional materials rises.

The costs have to reasonable/legit, but they are not capped by the security deposit in any way.As to the OPs question, I believe everywhere in San Diego county, the traditional security deposit without any special circumstances (pets, water beds, etc.) is for the security deposit to be one month's rent. 

There are multiple non-traditional routes you can take to make a deal work especially in markets like we have here in CO.

My market is fairly small and I’m not a tire kicker he knows I buy and sell with him traditionally so while my commissions might not be the biggest they are steady.

It will be hard enough getting a traditional loan at your age.

As far as buyers, we’re mainly only seeing well-capitalized savvy investors who know their market very well and can identify a good deal, cash buyers, and buyers with large investment funds that they can get margin loans from for less interest than a traditional mortgage (really common in my market right now).