Whirlpool tubs are no longer trending. They are too loud and don't allow the water to stay warm. I would not keep the deck and the step.

The tub doesn't need to be white.

Thank you! 😊

The greatest cost will be in labor. Your entire bathroom will need to be gutted down to the studs. Fixtures will be a much smaller cost compared to labor. You can keep costs lower by making choices that require less labor. Keep your sink, toilet, tub and shower in the same locations. Moving them around will cost more. Select tiles that are less labor intensive to install. Select standard size shower doors, standard size vanities. Custom anything costs more.

Whether or not you can forgo having a shower curb may be a matter of local law. Your bath designer should be able to advise you, and so should your contractor, who will have to pull the permits.

Suggestions: How would you design the counter space to keep an area for sitting do makeup, curling hair etc. et etc