A few years ago, we had to have a lot of engenieered floor that was glued down pulled up due to water damage. It was messy, in that they just busted it up and used long handled scrapers to get it up and the glue. Not really so much dust as just mess from the material. The problem I had was they tore up many a door frame.
When you sign with a flooring company, they usually have you sign a waiver that they are not responsible for anything that gets torn up in the process (ie: door trim and base mouling) so be ready to replace/repaint that.
We had the floors floated and a glue down wood put in that can be finished on site. It did require sanding first (on site) and I was surprised at how little dust there was (compared to that my house seems to grow lint, dust bunnies anyway). There was some, dont get me wrong, but not the nightmare I was expecting.
Good Luck

Not exactly the same situation as yours, but I am currently in the process of ripping up a 1/2" subfloor on which linoleum rests to put down bamboo. I am using a circular saw at the right depth to cut strips in the floor. The dust from that gets everywhere on that floor (no evidence that it defies gravity and goes upstairs). So, I'd say the answer to your question depends on how the demo is being done. If it's a smash-up with minimal cutting, you probably won't have too much dust. Also, if they will use a vacuum to get out sawdust and the vacuum has no fine-particle filter, guess what happens.

Well the way I work nothing gets destroyed in the process. However, it can be a dusty event, so you may need to tape off doorways. Also, set a few window fans near the work area and exhaust air to the outside. You will be amazed how effective just a little negative air pressure can be at reducing what settles elswhere in the house by moving air to the outside.

If your wood was glued down with a urethane adshesive, your contractor may be in for quite a lot of work.

Make sure the HVAC is turned off during the removal.

There are machines designed to strip tile off floors, and they also work on ;engineered' flooring pretty well.

How you treat planks that extend into other rooms depends on what the new floor will be.

If it is not the same, any planks extending into another room need to be cut off at the border cleanly (and that alone can be a problem).
Using a carbide tipped router bit set just above the concrete leaves a pretty good edge.

Thank you all for your responses. I'm expecting the worst (which is based on the original install and the mess that was made after just a few planks were replaced...this work is being done by our builder's subcontractor who installed the original floor). The flooring is the same as the rest of the house so we won't need any kind of border between the two. I'm going to ask if they're going to use fans and vacuums. I already told my husband that I don't want them using our central vac. Thanks again.