You can purchase an expandable plug at a plumbing supply store. It won't be flush (no pun intended) with the floor, but will be a lot less in the way than the toilet.

cplover - did you look to see if you could find the manual that goes with these toilets? You might be able to tell from that. Otherwise, there should be a contact number or email to check with the companies on these products. I can't imagine a company making a toilet that you had to remove to change the seat. Not that you do it often but from a general design perspective that would not be a good design.

In my area, handyman charge is around $150 and often includes picking up the toilet at the store and taking old toilet outside for disposal.  This might be a good opportunity to test out a plumber before an emergency happens. Ask around for recommendations and call a couple small shops to check out price and service. I don't want to call anyone who advertises widely.  I'm looking for the guy who leaves business cards with previous customers who happily pass them on. I don't like big companies because I want to hear the same voice and see the same face next time and I want to be a known destination to them also, not just another phone message to return. Plus, if you are a repeat customer, you are more likely to get a visit in case of widespread emergency demand.

Thanks for the responses! Turns out they caulked the entire underside of the toilet to the floor. Not just to seal the edges. Large wrecking bar worked great! Made the perfect stress reliever!!