Interesting! It didn't occur to me that the Earth's orbit might not remain at 1AU. (Begging the question of whether we will redefine the AU always be the distance from the Earth to the Sun, or to always be 1.4960E11m.) The tidal bulge part either has a major error or else a severe oversimplification - things that spin FASTER have a tidal bulge, not things that spin SLOWER, so a larger Sun (which spins slower) should have less of a tidal bulge.