Consider the time and energy you'll need to contribute, and let those factors guide your decisions.

I need to understand how much this would impact the ARV before making a decision.

Would it be a poor decision? 

As @Ke Nan Wang said you have to hire an architect to make these decisions for you.On my projects I will compile like 5-10 inspiration photos based on projects I've done in the past, comps, and photos I find online, then I'll present those to the draftsman/architect.

You’re asking the right questions, and it’s great to see you thinking strategically.My Take on Your SituationSince you already own a rental and want to expand your portfolio, your main decision points are:1.How to pull equity to fund your next deal2.Whether to transfer your current rental into an LLC3.How to position yourself for long-term growthHere’s how I’d approach it:HELOC vs.

This post reflects my personal experiences and opinions, so always do your own research before making any final decisions.

My other advice is to make sure this is the best decision when balancing your family and finances.

Remember, not every single decision in your life has to make financial sense.

Of course, that's a personal decision.

I don't make that decision.