I'd like to know how they installed the vanity in he first place. All I can think is that they left the extension off until the vanity was installed and then glued it into the fitting in the wall. The correct answer would be to cut out drywall, drill holes in studs and get it where it should be. Easier option would be to put a 3" filler on left of vanity so that you have room to cut pipe, install elbow and move to the back. It would then be easy to drill a couple studs in back and get it where it belongs. As for the tub, perhaps the drain can be swiveled to the left and extended out. The pesky overflow is a little less forgiving.

In one bathroom I got the tile-in semi recessed toilet roll holder and tile-in ceramic brackets that for a towel bar in the shower. They blend with the tile. In one bathroom I had a custom, fully recessed toilet paper and spare niche fabricated out of Corian that fit in with the tile layout and matched the tile. For towel bars in this and another bathroom I used Kohler Purist Grab Bars. I like using grab bars that are well anchored for towel bars because first, they are more sturdily mounted. and second because they can be used as grab bars for assistance now or later in life. Because I obsess about such things I also bought some extra so if I want to add some in 20 years I will have ones that all match. I personally do not like fully surface mounted toilet roll holders, so where the recessed ones went, and where all the towel bar/grab bars went required that this be thought about in the Framing stage of the bathroom. Because the recesses and framing can't interfere with each other and you need extra blocking for proper grab bar/towel bar mounting. I think one of the reasons that surface-mounted ornamental sets including the toilet roll holder and such became more popular is that nobody needs to think about where it goes ahead of time. I rarely see an old bathroom (1920-1970) that didn't have recessed or more built-in/permanent looking roll holders and stuff. (Especially toilet roll holders). Partly it was because the area allowed for the toilet was smaller, too (12" on center vs. 15-18" today), but part of it is that nobody needs to think about it until it's time to stick it up. I work in an office building and they remodeled the lavatories and went from stalls to cubicles where the toilet roll holder was surface mounted and one by one each one was pulled out of the wall because people used it to hoist themselves up. They had to change them all to those big commercial style holders. Long answer, but in general, I like grab bars for towel holders and I like them to be more ornamental and coordinate with the bathroom rather than the utilitarian sort. Kohler options are pretty expensive, especially Purist, but I figure I am doing it once.

I screwed up - it's a master bedroom and bath in the basement with walk out. You are 100% correct with the confusion. What I've decided to do is to have this be more of a "guest master bedroom" or future inlaw place. Every home is initially designed for the current occupant but also with future occupants in mind. Therefore what I'll do is focus on the upstairs primary bedroom and then if I do decide to stay, I'll give this to my soon to be teen-age daughter and I'll build my primary bedroom in the basement. When someone comes to look at the home to buy, they can look at the downstairs as a large "room" which could be a bedroom (staged as such) and an awesome bathroom ideally suited for a bedroom or just an awesome entertainment room.

The problem, of course, is that the bulb is tucked up inside the housing so the light is directed only downward. You could install something like the retrofit Halo SMD whose flat lens is slightly below the ceiling resulting in light dispersed in all directions, including reflected off the mirror. If you could remove the housing from the ceiling, you could replace it with a canless fixture such as this Juno WF6 or Halo HLBSL whose lens is flush with the ceiling. When you remodel you'll want to add fixtures on the wall. -- amateur