On a slab or crawlspace? Doing plumbing changes on slab is very expensive. Average bath renovation are around 15K without doing any plumbing relocation.

You should really talk to a local realtor about the effect that your ideas would have on your home's value. But yes, losing a bedroom would have a negative effect on value that a larger bath would not compensate for. Also, below grade bedrooms do not count as habitable space for an appraisal.

We have a full basement underneath, so we have complete access to all of the plumbing. Our garage, basement door, water heater, and workshop are located under the bedrooms, with the rest of the basement dedicated to the laundry room, game room, and wet bar.

I just did a budget remodel with bath. I believe 5k might be low, but I am in a higher cost of living area.

What materials do you plan to use for your bathroom? Non-fancy, non-expensive manufacturer of shower fixtures can run you $1000 alone (for valves and shower components). That is not including any shower surround/tub/floor material/toilet/vanity/sinks/faucets, etc.

I think your general layout is okay, except...
where will you put the bed?

Can your reach in closet be accessed somewhere differently and that opening closed off so there is room on that wall for other things? Right now, you have no wall in your master "free" of obstructions.

Kirkhall, our bed will stay where it is, which is under the window opposite the bath. As far as the reach in closet goes, we will probably remove the closet frame and have it be a nook in the bedroom. There is a bedroom on the other side of the wall, but it already has it's own reach in closet.

Geoffrey_B, thank you for that breakdown; it's very helpful to see what others have paid for something similar.

As far as the closet, I hadn't planned on purchasing a full closet system of some kind, as we need primarily hanging storage.

I did one very similar to what you have planned. Only difference was enlarging the bath a bit and putting access to the closet from the bath. That gave more wall space to the bedroom which they needed.

We added an 8'x10' bathroom upstairs, and, along with floorplan changes in 2 bedrooms, and the associated wall demo and construction (including adding 2 closets), it cost us around $10K. It was all DIY, using mid-range materials and glass doors on the shower. So your cost should be less than that.

We're currently gutting to the studs a 5'x7' bath and replacing all the house plumbing, so a close equivalent to what you're doing, except you're also adding walls and a closet. Our budget is $1K for the bathroom and $1K for the plumbing.

So bottom line: I think you can do it for $5K if you watch your material choices and DIY everything. Average bath remodels may cost $15K, but they're also typically hired out.

As for resale, I live in a basement area and in my experience, many/most people are looking for a certain number of bedrooms to handle their kids, and they consider basement bedrooms in their calculations, even if they technically "don't count" for assessor/appraiser purposes. In fact, there are some people building new homes that put the master on the main floor and all the kids' bedrooms in the basements (I wouldn't do that myself). So there may be families with young kids that want all the bedrooms on the same level, but others with teenagers may actually prefer to have a basement bedroom to put their teen. :-)

A 6' wide walk-in closet will be a little tight, with just 2' of walk space between the clothes. But it's doable, and better than you've got now, so I don't see a problem with it.

You can get a decent shower valve/fixture set for $300 and change. We bought all of ours on ebay, and they've got separate temp/pressure controls. See one example linked below.

Good luck with your planning!

Here is a link that might be useful: Delta faucet set on ebay