Trade or business activities are non-passive income, such as flipping properties, new construction for sale, and any kind of just pure buy/sell. 

I don't think trying to time the market is wise, unless you are purely a speculator.

For the split, I'd say going pure business mind of it, what does it all cost and return without the partnership, what will it be with the partnership, then what is what each brings to it worth and make some agreement the matches the differential, that would be my max split.

But as a pure rental investment, this one is not very good.

Now - this is a house hack, and as such it shouldn't be evaluated as a pure investment.

@Brandon Goris If the OP can generate that sort of income, they can likely drive a solid 8% ish return on invested capital purely from operations.  

No conventional lender makes a pure purchase money loan without proof of funds, it's a legal requirement under several regulatory angles, money laundering, drug money or illegal activities etc. with funds needing to be verified as to the source of funds or held for more than 90 days.

Quote from @Lawrence Briggs:  That's the face of pure joy.

If you are purely looking at cost per sq.ft. modular doesn't make sense.

Unless you are on point doing this yourself or want to hire someone to do it for you, I would guess this would be an OK deal, but purely a guess.