No doubt that you can add many things to the structure to make it suitable to your desired outcome or the buyers needs but you still have many limitations due to space and costs.

It was actually scary once he explained how the weight of the roof was on empty space. 

Perhaps you should consider selling and buying a duplex where you could each have private space?

I'm referencing the non-qm space.

What do rental comps tell you that space would rent for once finished?

LEASE the space and finance ALL the new washers and dryers you need from a reputable distributor.

(When I'm just running numbers quickly for myself for investment properties I feel good just going with 3% - that usually gives space for lender fees and escrow fees....)

Ease of process may be a DSCR or Asset Based loan, but it's tougher to find those guys in the commercial lending space.

In a few months I’ll be living with family and paying $0 rent, which will boost my savings by over $2000 a month, though eventually I’ll want my own space - I’ll probably house hack, once I’ve picked an area I’d like to live in for a few years.What I’m not sure on is, how I should handle financing my first (and subsequent) property purchases.

I'm currently pouring everything I've got into fixing up a new office space, but once it's done then I'll invest only out-of-area.David Greene has a great book that explains the whole process.