@Sean A Lewis the only way to know if you can get your money back from a loan is by talking with a loan officer. Now, it is possible that someone else might be right...but I would still say to confirm with a Loan Officer. I'm saying this because later someone might give you tax advice - get with a CPA. Or legal advice - get with an attorney. It's impossible for us to keep up with EVERY industry out there. So, even if you hear "something"...having a good network will allow you to verify what's possible.
Here's what you need to know based on what you asked above:
1. Refinancing - There's isn't enough information for me to provide specifics...so, I'll address it both ways. First, you won't be able to refinance with a traditional loan with multiple ADU's on your primary home. Traditional loans through Fannie/Freddie/Jumbo lenders won't allow multiple ADU's on a property. Their guidelines actually prohibit this. Which means you would need a "non-traditional" loan to even consider refinancing. That means a higher rate and less favorable terms. But finding such a loan on a primary home would be extremely challenging. It might even be impossible. Secondly though, if this is an investment property then you would have more options. Same types of rules apply in that this would not be a "traditional" style loan. It may not even be a 30 year, fixed rate loan. This might fall into the 20 year, ARM products. But you could find those on an investment property as opposed to not finding them on a primary home. There's over 8,000 lenders in the US...I can't speak for them all but this is what you should expect. Multiple ADU's on primary home - big challenges. On investment property - options, but less favorable terms. If you just have 1 ADU, then your options will be SIGNIFICANTLY more plentiful.
2. Value - How do we know what your value will be here? We must consult our comps. How many triplexes have ADU's in your neighborhood? And this goes for ANY renovation that we do. What will my value be if I finish a basement? What do your comps show? What about with adding granite countertops? What do the comps say? Adding a pool? Comps! We MUST analyze comparable properties with determining future value. So, if no comps have pools...then adding one may carry ZERO value. That doesn't mean we shouldn't add a pool though. If adding a pool provides a happier family...what's that worth? That's priceless. There might be reasons for us to do these types of renovations still but you need to know that your comps determine the value. And if there aren't any comps, then no value might be something that occurs. Maybe adding the ADU's will give us more rental income and that's good enough. But keep in mind that resale in the future. So, just like it might be hard for you to get financing...same for any future buyer too. Keep the current market in mind but also consider the future too.
Hope all of that makes sense.