Theming can be $5-10,000 per bedroom (includes whole house decor, so a 5 bedroom could be $50,000 for the entire home furniture) depending on your imagination and quality.

If it does go to probate, hopefully your brothers and you can amicably go the informal route vs formal (I've worked with families in both when buying properties out of probate and informal is FAR easier).Since there's no debt on the house, maybe you could sell with financing or maybe you could even buy out your brothers with financing -- that way you maintain ownership and just pay them a monthly amount.

We had to bring the 1925 house to 2023 code which involved un-installing 26 windows that were already nicely installed (in appearance) in the house, reframing them to 2023 standards (at the time) which also involved strapping the bottom of the wood framing with metal straps (mind you this all after we had already completed the inside renovation).  

I plan to purchase a primary residence, multi-family home (2-5 units, 'house-hack'). 

Those already exist in mass.

Happy to discuss this further on what might make the most sense for your end goal.If you are renting right now and starting your path in real estate investing, as said above, I really do like the house hacking strategy for your situation.

Also if you are selling, hopefully your agent has advised you but good practice to have a vacant unit to open the buyer pool to owner-occupied buyers/house hackers.

When did the HELOC on my house with ADU, the first appraiser used option one and I demanded a new appraisal where they would give me a flat value.

Is it like you sold your house and don’t have to pay for the profit?

Usually in the year following your purchase, the property appraiser will reevaluate the house based on the new sales price.