Without knowing what the other grasses are, it makes the decision for us...we cannot use selective herbicides for it. Hopefully you have patches of it and not wide distribution. If so, hit those patches with 2-3 apps of round up (glyphosate). They'll wither away and then you can overseed bare areas. This, again, makes it tough because we don't know what other grasses you need to overseed with. I would recommend spraying before digging in case it is reproducing via stolons...kill it all. Glyphosate will kill whatever grasses it hits. To combat this, I have a set of all different diameter PVC pipe couplings. Actually, I'm preferring the reducers lately, like this: http://www.lowes.com/pd/Charlotte-Pipe-2-in-x-3-in-dia-PVC-Adapter-Coupling-Fitting/3132737 I select the diameter for the size of the grass I want to spray and place it over the top and spray inside the coupling thus saving the grass around it so you only have small bare spots. Now, if you have warm season grasses, those spots might fill right in, but that won't be the case with cool season...you'll need to overseed. Oh, this is important. That stuff, even if we are wrong, has seeded your yard. You'll want to look into pre-emergents like Prodiamine and Dithiopyr. These stay active in the top layer of soil to kill seeds that try to germinate...they do not kill your established grass. Keep in mind, that if you are overseeding, it will kill that too. You have to apply these later...I know Prodiamine is 60 days after seeding. Also, Prodiamine can last 8-9 months in the soil, where Dithiopyr is shorter and can last 3-4 months....depending on rainfall. In short: If you have cool season grass, kill what you need to now. Do your overseed project around the beginning of Sept, and put down Prodiamine around the beginning of Nov. If you have warm season, somebody else will need to comment, but I believe you seed that in the Spring, not fall. I would kill what you need to now and put down Prodiamine 2X between now and again in Nov....re-seed in April...if you even need to. Lastly, if you feel yourself becoming a lawn nut, consider a full renovation so you know exactly what grasses you have and can react accordingly (and with less effort) in the future. Cheers.

If you're in the US, contact your county's Extension Service office because they will know the common weedy plants in your region. Locate that office with this interactive map: http://npic.orst.edu/pest/countyext.htm

Look up shepherd's purse, Capsella bursa-pastoris. The seeds look quite a lot like your first picture, though maybe not exactly, so maybe it's a close relative. It is a very common weed in different continents.

Try comparing to Veronica persica for #3. I see you have some dandelion in #2, I would expect them to be bunny edible. If you have dandelion, chickweed, veronica, etc., it is obvious that you have broadleaf weeds and so I would look for plantain (Plantago spp.). Probably another one you can feed the bunnies.