Pull it out of the pot and check the roots. If brown, soft and mushy its rot from probably too much water. If white and firm then roots are good. The soil looks to be too heavy and a lot of peat. Once peat gets dry its difficult to soften again. Water will not be absorb and run right thru to bottom. I also think it just needs some tlc. Yellow leaves are a symptom of over and underwatered, but usually under they will be drier and crispy. I don't see any yellow leaf tips. Yellow stems IMO indicate something is wrong with roots or soil etc.

Looks like chlorosis. There are many reasons this could happen. Aglaonema needs a lot of light and a lot of heat. It needs at least 70 degrees, 75 is better. It's soil should never get below 65-68, bottom heat may be needed also. It could also be a deficiency. Try giving them a little epsom's salt, about 1/2 tablespoon to a gallon of warm water to dissolve it. Let it get to room temp and water both of them. Move them to a south facing window, you may need to supplement the light and heat. I would also check for spider mites. Put a white piece of paper under a leaf and flik it. If they are mites, there will be microscopic black dots on the paper.

Is it really dry air where you're located? It's not where I am. If it is dry air where you are, then the pebble tray is ok. But I think skip the misting for a while and see how it does. I wouldn't worry too much about your plant. Sometimes overthinking it can make you stressed and the plant doesn't do as well. I had to learn that by trial and error. I also learned that my prayer plant does best when ignored except for watering. No moving around, just leaving it where it is. So here is a photo of mine for comparison. I keep it in a 6" pot and medium light, and water it each time with a low dose liquid fertilizer. I never let it dry out completely- I let it go until the pot feels lighter, then I water. Plastic pots are best for these plants, with good drainage. It really should be hung from the ceiling now, but it does ok draping over this little hamper. At night, the leaves move so they are vertical, like yours in the first photo. That is why its called a prayer plant, like hands together praying. Also, weirdly, this plant likes to grow during our winter. I know that's strange, but it really does. Eventually your plant will grow large enough so that if there is a leaf with brown edges, you can just cut it off. I wouldn't do any trimming right now to yours though, because it's much smaller and needs the leaves to photosynthesize. Sometimes, if it's really quiet towards night and you set something next to the plant, sit and wait, you can hear and see the leaves moving because it gets caught on whatever is sitting next to it. Pretty neat.

If all else fails, put it bare root or a cutting in water. It should grow new roots within a week or two. The cuttings rooted in this way are easily repotted and take to soil without too much trouble. I found a part of my plant shriveling a week or 10 days back. On further inspection that branch just came off and seemed to have no roots. The leaves were quite leathery and dehydrated. I left it submerged in water for 3-4 days till the leaves and regained moisture and then kept just the stems in water. Sure enough, it now has mostly recovered and growing roots in water. The point of my story is that these plants are very resilient and hopefully it will revive one way or the other. I prefer water for suffering plants that easily root in water because it takes the guess work of good/bad soil, over/under watering out of the equation. Also, any soil born disease or infection. I might just grow this one in water permanently.