Theoretically you can install vinyl over tile. Possible concerns of doing that would be overall floor height and potential for grout groves to show through over time. Grout groves should be filled until flush with the tiles if you want to do that, and any broken tiles should be removed and either replaced (which you can't do) or filled in with something else hard that is flush with tiles.
You should definitely remove the toilet, at a minimum, during the vinyl installation.
Go with sheet vinyl (one big piece), not vinyl tile, if you decide vinyl works for you. It is likely worth getting a big sheet professionally installed.
Here is another idea:
If you are planning to sell in a year, interview a couple of high volume residential real estate agents. Say you are looking for someone to list the property when the time comes (true) and have them come by and look at those rooms and make recommendations. Individual tastes vary, but they know better than anyone else what will sell in terms of flooring/kitchen/bath right at this moment. I would hate for you to spend a whole bunch of money on a renovation, only to have real estate people and buyers decide it was either not worth the money or not in their taste.