If you are able to add a pic of your mystery plant to the discussion, somebody should be able to help you decide what it is.

Except for maybe the unknown one, the others seem fine at my house without futzing with stuff like pebble trays. But I do stuff like...
-Opening the door as soon as possible after a shower lets the steam flow out into the house.
-Boiling some water on the stove (which I do at least once per day to prepare meals.)
-Warming a mug of water in the microwave, then sitting on the floor near plants while it steams can help (more-so while the heat system isn't blowing air by plants too fast for this to have an effect.)
-When I use my oven for savory (might mess up some baked stuff,) I put a pan of water in there too if it will fit, to steam while the oven is on.
-If your air registers are on the floor, and doing so won't be in the way to trip people or get spilled, sitting a pan of water really near them would help add a bit of humidity whenever the air is blowing.
-Moisten a towel and hang/drape it somewhere near plants to dry.
-There are various kits/adaptations you can get to vent/filter your clothes dryer exhaust air through water, then into the house for winter. That adds lovely warm, moist air while running the dryer.

Wet leaves are not the same thing as humidity. Misting the soil surface might help more in that regard, as long as you don't continually add enough moisture that it goes into the realm of constantly watering plants.

FWIW, I'm hoping plants like to take a steam, and/or that I've picked ones that do. Our bathroom has a high ceiling, but the shower walls don't go all the way up. A repurposed closet door is now a slotted shelf where a few plants are taking refuge from the winter cold for a few months. They definitely have been getting profusely steamed a couple times a day.

thanks. a lot of good ideas.