What works best to remove chickweed?
The first two photos show the seed pods of hairy bittercress. The third photo is, indeed, chickweed.
Keep your lawn mowed to prevent chickweed from out-competing and shading your grass. It will naturally die in late spring, after dumping tons of seeds. Mowing helps keep down seed production, too.
Both chickweed and hairy bittercress are not a problem in thick turf. They are an indication that your grass has thinned out and needs to be reseeded. You can do this now, after mowing and raking, but the best time to overseed is in early fall.
Here is what you need to know about lawn renovation:https: //extension.umd.edu/hgic/topics/lawn-renovation-and-overseeding