1) I can't tell for sure without seeing it, but most likely, yes. Even if it wouldn't HAVE to be removed, I can guarantee you it'd make things so much easier. 2) Absolutely. I've done this many times.

Great comments! Thank you for helping me to think about this out loud ;-). We live in northern California, one hour south of San Francisco, and a half hour from the beach in Santa Cruz. The area is pretty pricey and most single-story houses are being converted into second story houses, some of them good, some of them not so good, AKA monster homes :-(. We are baby boomers and like the size of our house, our garden, etc., and the fact that it is a one story. It's perfectly fine for the two of us. I took care of my Dad before he passed and he was in a walker. I like the idea of having a higher ADA toilet, grab bars, small corner bench, separate hand shower, fixed shower head, and low curb for the shower. And, we are not without our own aches and pains in the joints and lower back! jkom51: thanks for the tip on looking at cultured marble/cultured granite. I am liking the looks of carrera marble a lot, but I'm not sure if it will be too slippery and hard to clean. I don't think I can steal room from the two adjacent bedrooms because they are very small and I wouldn't want to lose a closet in one of the rooms. I guess this is another reason for one, nice, big shower because it opens up the little bathroom. I am seeing the frameless shower door in there.

I keep revisiting this thread, hoping for a Sign. :) Is it ever acceptable to use a shower pan and create a tile threshold over it, thereby making it higher? As for cleaning the nonskid elements of a shower or tub. I have some wonderful nonskid strips in my otherwise very slippery acrylic tub where I take my showers. Yes, they pick up and hold grime a little too well and you can't just go gangbusters cleaning acrylic. The other day I used some Softscrub and a curved nail brush that fits around a couple of fingers. With very little elbow grease ALL the grime was removed and the shape of the nail brush is very ergonomic.

Sorry. No easy way. I would want the new lap that seals to the wall membrane above the curb. Which would mean replacing the existing curb, removing & replacing a couple rows of wall tile. It's a difficult and risky undertaking. No guarantee the tile will come off the wall without damaging the Kerdi membrane. If it's Kerdi board forget it. The paper face will peel off. Sadly in this scenario your best hope is the wall tiles were installed poorly and that's not a good thing to hope for. I would research ways to refinish the existing base if possible. You never know what new products may be available. Sometimes there are options never considered. https://www.labourmatters.com/teak-shower-floor/ I considered Joe C's thought. Flex in the base would need to be eliminated. Yep. thinking outside the box. Porcelain pavers on pedestals? You have my gears turning:) https://www.google.com/search?source=univ&tbm=isch&q=pavers+on+pedestal+system&sa=X&ved=2ahUKEwiho8GCxbjvAhWYbs0KHYEQAmwQjJkEegQIFhAB&biw=1227&bih=567 Disclaimer - None of the above the above thoughts are approved methods:)