Strong engineering consulting (local tends to be better), Designer/Architect with a strong relationship with a Builder (ideally having completed projects like the one your proposing),  Legal (To get your offering documents together or real estate transactions) and you'll be adding more and more as you go.I started out as your traditional buy and hold landlord and have transitioned to development, but I did it by joining a team that already had a bit of motion behind it. 

Can those that are missing be added?

Keep in mind, that while you may be adding doors, it doesn't diminish the work-per-door your PMC is doing. 

Any of those, "we buy houses" signs with a phone number, give them a call, tell them you are an investor looking to be added to their buying list and what you are looking for. 2.

All costs will be added to rent payable on the 1st.In another line it is spelled out that all plumbing issues are the responsibility of the resident.

If you are not planning on refinancing then you may want to just be added to the deed with your sister during the initial purchase and work our an agreement with her for how the equity, cash flow, losses, repairs, and such will be split.

It will be added to the lease agreement.

Your major cost will be adding the bathroom.  

Anyway, I mention all this to say that there is a lot of value that can be added in subdividing if you find a good lot. 

I'll be adding a 3rd story and roof top deck along with the other renovations throughout.