It depends on how extensively you wish to remove the plumbing. If it's just pulling out the fixtures and capping, you might be fine without a permit, but if it's more than that, I would say you likely will need one. Your licensed plumber should know whether the permit is warranted. I don't know about your HOA ... if it's an attached home, they're more likely to care, as it could affect others, where as detached home HOAs are usually more concerned about changes visible from the exterior, but it's possible that the change in valuation of the home (loss of bathroom) could matter to them. I'd ask to be sure. Price will somewhat depend on your area, but I usually assume $150 for the plumber to walk through the door. If you're doing this DIY, it'll be a whole lot cheaper. Don't forget to include your disposal costs (I assume you're not storing the old toilet.) Getting the plumbing to a site is the expensive part, if everything is there and capped, it's not a huge cost to convert back. It's mostly the cost of the fixtures (and the plumber still costs $150 to walk through the door). Going from powder room to closet is not the common ... usually renovations are going the other way. If you're asking about it being a DIY, replacing a toilet is often DIY, so the removal part would be simple, but make sure you know what you're doing with the capping, or you could end up with a stinky situation.

A 1/2 bath i.e. powder room is not much of a resale issue as long as there is a bathroom accessible to your guests without having to go into a bedroom. A condo with 2 full baths is very salable. Adding a full size washer/dryer makes it even more marketable. I would recommend doing that remodel which will give you the full size w/d-it will add to your enjoyment of your home, and will be easy to market at resale time.

@enduring we are seriously considering a stackable washer and dryer to make it more functional. We will hopefully get quotes soon and make a choice. @Kate Your laundry is definitely my goal! It looks so much more functional. Which front loaders did you go with and do you like them? @HU-187528210 yes, I agree. We would need to bump out that closet. we lose a bit of living room space and a closet, but a functional laundry room is a great trade off.

too bad the contractor didn't try and round those sharp edges on the wall. wouldn't have taken much to do something like this. (ignore the style) I would hang a mirror under your lights and some art or a few shelves on the other wall. vanity tray w/a tall plant or stem leaves will buy some veritcal space. see how they did this one on the side? I also like this black wall in back of the vanity. look for a paint color w/red or pink undertones. you have warm, reddish/yellow flooring, and the countertop is a taupe/beige w/pink slightly yellow undertones. Stay away from anything cool, or blue/gray or green. It's a powder room, have some fun w/it! these pendant lights in that corner spot would be a cool idea