I haven’t personally run 1E ToEE, so these comments are general based on my experience in running a lot of 1E->ACKS conversions and a lot of modules written by Gary Gygax.
AC: ACKS AC = 10 minus 1E AC. Unless you have an excess of free time, I wouldn’t worry about re-calculating the monster stat blocks other than that. Yes, there can be a 1 point difference between ACKS plate and 1E plate, and a 1 point difference for DEX 18 (-4 AC v. +3 AC). But that means the biggest difference is 10%.
Loot: My experience in running Gygax/Mentzer modules is that they tend to be more difficult than other adventures for similar level characters, and that they tend to give more treasure in exchange. As a result I generally see a higher body count, with faster leveling for the survivors.
I’d recommend you take the most minimalist approach you can to adapting the module, making only such changes as are strictly necessary.