This is a really big project on a really small budget and in need of onsite professional advice to see how you might be able to achieve your goal.

Just a few thoughts: Moving plumbing on a slab is a real issue (i.e. expensive) so you might want to see what could be done in the current footprint. I would be inclined to leave the shower/toilet where they are with some minor refreshes, and look to the other room for your tub space. You need a drain and hot & cold water for a tub, so close proximity to the current sinks is the most logical location for your tub. Think about what you will be looking at while soaking when you consider the orientation of your tub, Not sure if you will also be able to do a double vanity as well as the tub and if there is room then for a major closet overhaul...

Sometimes a good purge of your current closet's contents followed by a better organizational system will create more room in the same space.

Can you also post some pictures from several different angles of the current bathroom and the view from the master into the bathroom?

My waterproofing, tiling, shower fixtures, tiles, glass and labor for just over a 3x5 shower cost more than your budget. 15 k might cover a new shower only. You might want to reassess you wants or adjust the budget.

You don’t have a hope of accomplishing that laundry list on that tiny budget. The typical 5 piece master costs 40-80K. Houzz photo level is 80-120K. 15K isn’t even materials cost.

http://www.remodeling.hw.net/cost-vs-value/2018/

Sophie, having just gutted two bathrooms and a kitchen I would have to agree. My master closet cabinets with island were significantly more than the cost the OP wants to spend on the entire project. And that was just the master closet. However, the OP should plan the space then get bids and access what are must haves versus what she wishes. I deleted the tub because I don’t take baths and I wanted a large shower. As long as she has a tub somewhere in the house it is not an issue. At that point, she will have a better idea of what her budget should be, but based upon the space I would guess closer to $50,000

I just want to echo what Roarah wrote. A friend of mine just replaced one of those pre-fab plastick-y shower stalls with a new tile-and-glass one. She did not have to have plumbing lines moved, the new shower took up the same footprint as the previous one, and she didn't touch the rest of her bathroom. She was complaining to me that the labor, tiling, niche, showerhead/taps, and glass stall cost her close to $15k. Just so you have a realistic idea.

Thanks for all the comments. We plan on doing a lot of the work ourselves as my family has a lot of experience in construction - so the labor cost are not as much of a concern (sorry for not mentioning this earlier). We are really looking for suggestions on layouts/floor plans for maximum utilization of space. Appreciate all the ideas and look forward more comments.

Then hire a K&B designer. That expense will save you way more than the cost.

the bathroom you want seems to require more space than before. unite the wall between the vanity and the toilet will look spacious and comfortable, you can separate it with large glass, for that, I have a picture that may fit the bathroom of your dreams. I hope this can help ...