No need to buy all new just find some one with an ovalizer
2nd. Ovalize and insulate. I'll bet BGs pension that you don't have the 2" clearance. I just went thru researching this with some help here. Also, tile removing can be insanely easy or a terrible job. It all depends on how tight to the blocks the tile is. I have literally removed 20' of tile in an hour or so and I have spent hours trying to get the first tile out.
There is a thing called a tile smasher, or I call it that, it hooks to a drill. If you lower it down and spin it slow and start hearing a hollow sound from the tile when they are hit, your probably in good shape. If it sounds like a dull thud, you may be in trouble.
Crap, even without an ovalizer, you can, with some patience and a 2x8 ovalize that liner yourself.
Sad to say first project I had to punt on! With connections from oval to round I just could not get the clearance to get it attached. I am going to try and have a shop make a new connector for the stove in round so I can gain some room. I was using a Vermont castings piece and it is just way to tall! I am so mad right now!!