You probably could let the water settle down and then use a siphon tube to remove the gravel residue and dirt which had been lodged in the gravel.

Rinse the new gravel outside, both so you don't get any down a drain and so you don't breath the dust. One or a couple of times breathing it probably isn't a threat, but there is actually a breathing disease which people working around gravel and stone processing get. It is called silicosis. Rinse the gravel until almost all of the "dust" is gone.

Let the temperature of the gravel get about the same as your fish tank water. Add it gently, fish have much the same ear structure that we have. They just have scales and skin covering it, rather than a cartilage lobe acting as a sort of funnel.

Measure your ammonia and all that. If you have a functioning and cycled filter and feed sparingly for a while, the loss of the gravel may not throw the nitrogen cycle completely out of whack.

Don't sweep up a lot of the gravel in the net at one time. You don't want to stretch and/or tear that net.

I appreciate the need to get rid of gravel from old, inherited aquariums. I also doubt that the gravel should be more colorful than the fish. And light hued gravel will cause the fish to fade and not show their best colors. It always amazes me that shops would use white or tan gravel to show off fish they might want to sell! ;)

Once dried out a gallon of brightly colored gravel in an aquarium from a garage sale. The dry gravel was poured into a gallon milk jug and stored in the trunk of my car. When I got caught in a snow storm near Lake Michigan (after a college class), some of that gravel was poured/ packed under the rear wheels and I easily drove out of the parking space. (Wonder what the owner of that property thought, when mowing the lawn the next spring and encountering the rainbow.)

Enjoyed your reflections and thoughts in this diary. This isn't a writing class, but it was obvious that you put quite a bit of effort into it. Good luck with the redecorating.