Just don’t let what you cover them with touch the foliage. You’ll probably be OK. Some things are more sensitive than others. Impatiens don’t need much frost to blacken them. Marigolds are pretty tough.
If your annuals are still blooming at this point, then they’ll keep going until frost or a hard freeze. Some annuals poop out if you don’t keep them deadheaded (because once they produce seed, their job is done), but that doesn’t seem to be an issue in your case.
Whew, I got the driveway pots in the carport and the ones on the deck covered. Geez those pots were heavy. We had a hard rain last night. I had two 14 inch clay pots that felt like thirty pounds. That miracle gro potting soil holds the water. I dragged them to the carport. I need to buy a plant dolly from Home Depot ASAP.
Also tipped out the water from the saucers. didn’t want the plants sitting in ice water. did that for the roses too. Although my roses are rated for 15 to 20 degree weather. they shouldn’t mind this 32 degree nights. so the roses didn’t get covered.
we should be back into 40 degree nights in 4 days. At least that’s what the weatherman promises.
Once we start getting 32 degree days then I’ll give up the war. Let nature do its thing and kill my annuals. Not much else I can do. I don’t have room in the house for all these pots.
It’s not hard or expensive to set up a DIY greenhouse - some PVC pipe and clear plastic sheets set up in a lean-to arrangement or against a wall should take care of it. The sheet alone will do the trick if you don’t have time for more.
Some plants do die back every year no matter what you do - kind of like how deciduous trees lose their leaves.
PS: You mention tipping water out of saucers - be careful about too much water in the pots themselves as well. I’ve lost several pots over the years to freezing water. It expands inside the pot and cracks it open.