Mine took three weeks or more, but I had to demo a 1970’s walk-in shower before I got to putting in the new one. I had two bagsters of mortar and tile, and had to re-sheetrock the walls and ect.
Your mileage my vary based on how much is needed for the swap. Just expect that it will take longer than you think.
I just removed an old walkin shower with a tub/shower combo. In answer to your question, yes its possible. That being said you should plan on it taking a while to complete if you need to change any walls or plumbing and thats if you don’t run into any strange issues. An extra person is very helpful to help get things into place. If you have a lot of room that might not matter.
Is this based on a gov ID? I didn’t see that in the article.