I'm considering doing a 50:50 equity partnership with one of my associates and was wondering if it's possible to structure a househack in a way where I would be living in it (for at least a year) while my partner does not.

How many years until the child lives there?

After you have lived there for 12 months get an approval to build or buy another 2-4 unit home to start the process all over again.There are some tips and tricks to speed up the process to ensure you can buy or build another 2-4 unit. 

I wanted to know if I should make another bedroom where the living room and dining room are located.

I wont live there.

This is also why price point is lower, but again, Philly is philly, and will always be philly - a place where lots of people live

We need this house rented to lower our DTI.We want to buy small MTF in the future to househack in CA using low downpayment maybe FHA loan.Thank you in advance I love house hacking & all about co-living and room additions.

. :-) Not to worry, the public will move to where they can afford to live and that will affect prices up & down the scale. 

best strategy: buy large house with adu, rent it outdone, live for free in bay area, checked.for income, forget all about one hundred dollar cash flow from real estate, go for thousand dollar cash flow from TSLY/NVDY/etc/etc LOLfor real estate, just flip when you had the best opportunity, sell it again in few months or two years for 100-300k profit.dont think cheap in bay area lol

There are costs associated with doing a HELOC.If you WILL be living in the property for the first year, get a 5% down, or less, FHA/Conventional/203(k) loan for the purchase and keep more of your money in your pocket for future purchases, repairs, etc...On the second property, use a private lender to fund the acquisition/repair costs if any, and refi out using a DSCR in 3-6 months.