It would qualify under Section 121 of the Internal Revenue Code (i.e., the 121 Exclusion) as long as you can say that you have lived in the house as your primary residence for at least 24 months out of the last 60 months. 

I would love to find a mentor and/ or maybe do sum interning.

Furnace components are available without needing to replace the entire unit.

Typically components will be settled with like kind and quality and the lesser of the cost to repair, replace, or in the event of a total loss The coverage amount you have on the dwelling.Now, you can still do replacement cost and save a little money by having the value at 80% of the replacement cost - Replacement cost = $100,00080% of RC = $80,000Doing this will still afford you the benefits of replacement cost.What I've found in my insurance career is that independent agents are the most knowledgable and have the most options for you to properly assess and cover you.

Kinda like interning or shadowing, ideally to help really get the hang of it without making a ton of costly errors.

If you are using closed/open cell spray foam, you need to make certain the bricks are able to breath and dry - otherwise they will spall - so normally you do not want to apply the foam directly to the brick.If the building is structural brick, then there may be an internal framing for walls, but more likely there will be furring strips attached directly to the brick.  

Please allow me to analyze the multiple components of your situation.Long Term Tenant: At 4 years, this is a long term tenant, and this may incline you to say "I don't want to ruin the potential for future long term residency with this tenant.

You can't do those kind of numbers on regular rentals.Check out the podcast #140, BP Podcast 140: The Riches Are in the Niches (Like Student Housing) with Bill SyriosI've internalized this particular method and gone after niches, myself.

Then, will generate architectural plans indicating the demolition of internal partition (One wall), plumbing fixtures and gas lines. 

The dollars component will never overtake the relationship component a broker/agent provides to completely automate the process etc.