Thinking Oscars

Hello all,
I have a 100 gal freshwater that currently has 1 irridescent shark, 1 red
tail, 1 marble angel and about 6 ottos and/or khuili loaches. I'm
consdiering a major change and converting this tank to house 2 or 3 Tiger
Oscars. Since I'm not very familiar with cichlids, I thought this forum
would be the best place for answers.

So here are my questions:

I heard that Oscars like to rearrange plants, I have a large amazon sword
plant (18"h x 20" dia foliage) currently in the tank. I intend to remove
it, but if I kept it, would the Oscars rip it to shreads?

Would it be advisable to mix my current fish load with 2 Oscars? I'm
particularly concerned about the two sharks and angel fish. The rest I
expect will become breakfast at one point or another.

What about a Jack Dempsey?

Snails or Pleco for algae control?

Finally, I also have a 20 gal I was going to breed guppies in. Nothing
fancy. Any thoughts on a periodic diet of guppies for the oscars?

Thank you,
Justin