My advice would be to not pay for the layout change to show on the plans, it isn't structural and can be changed onsite during construction. The size of the vanities wouldn't change much.

Our friend is the person who will change the plans, so cost isn't a concern. I just want to figure out if I need to move any of the shower or water closet walls to accommodate placement of the 6 ft freestanding tub I have selected. I don't want to have to make any more changes and prefer the plumbing plans to be accurate. I penciled in a tub in the corner, but it seems it will stick out quite a bit, so I'm wondering if it would work better another way.

I don't understand having a drying area, I would make it all one wonderful shower. Then, if there's room put the tub on the wall where little vanity is. Make the rest one big ole vanity with two sinks.

That's simple. When you select your builder, tell him/her that you want a freestanding tub in the corner which shows a built-in tub, so the wall and flooring tile will go continuously into that corner. You will purchase the tub, and prior to the beginning of construction, you will provide the tub installation information for proper placement of the water lines and drain lines. Builders are used to changes being made on plans. Whoever is responsible for purchase of the bathroom fixtures will add the tub you select to the list. You will undoubtedly be involved in the selection of materials such as tile, counters, fixtures, carpeting, flooring, appliances, paint, etcetera. Whether you make the purchases or someone else does, your participation in the planning is necessary. If the plans you bought included specifics on all those items, you still have to be involved in order to end up with the home you envision.
Before construction starts, you will want to begin working on a color scheme for the entire house. If you already have Houzz idea books, start going through them for color, kitchen, and bathroom ideas and move inspiration pictures into new albums for your new home. You will be making many decisions, so that is your homework now, working up to the point when you will need to make those decisions.

We are building our own home, this will be our 2nd build :) We also have a retail store selling discount home goods and already have the bath tub. I have considered switching to an oval tub that would fit better in the corner, but I love the one I have so I'll try to work with it. Here is a pic of one suggestion I received (Image is reversed) but this is the one where I think the tub sticks out too far next to the vanity.

I am not sure where the master closet leads to, but it makes more sense to have access from the bedroom then the bathroom.

Corner bathtub by the windows, use larger windows (4-5') double vanity at entrance to bathroom w/ linen or makeup vanity south of tub. Move toilet closet to where the shower is currently shown and include a huge walk in shower.

That is an interesting concept for sure. I think I would have to do a smaller tub to if I leave it in the corner.

For some reason I feel the walk in shower is hidden. Id give up closet space to give the actual bathroom more space.

I think BeverlyFLADeziner's solution is best. But assuming you want to keep all the other fixtures exactly as they are, to tuck in a freestanding tub exactly where the corner tub is with minimal other changes means you'll probably lose 6" -12" from the longer vanity to the right of the tub

BeverlyFLADeziner I can see now that with this layout, if I use a smaller tub, I could have room to extend the vanity and even do a knee space with a storage unit on each end of the vanity, or skip the knee space and put a storage unit in the center between the vanities, I love it.

I played around with the idea of moving the door. It makes more sense to me that the bathroom door be on the end of the wall closest to the bedroom entry door.

I thought it would be pretty if the bathroom door lined up with the tub and lined up with a window, but it creates a potential privacy issue if you have to go through the bathroom to get to the closet.

You could use pretty freestanding piece of furniture for more storage here in pink...