1) if it smells strongly, it's bee balm. if not, it's a weed.

2) I see clover, and what MAY be marigolds. but whether they are nice marigolds, or weedy ones, is anyone's guess.

3) looks like some kind of bramble to me- that's one I would take the foaming roundup to, you'll never kill it by pulling it out- you'll be too busy pulling thorns out of you paws.

4 ) dig one up. it it has a round bottom, it's a gladiola, put it back in the ground, it's on its way. but I THINK they are young irises (they will have a finger- like rhizome at the base of the plant.) they like to have the top of the rhizome up above the surface of the dirt, so brushing the dirt away from them will help...they should bloom next year, and you have the beginnning of a nice clump there.

5) not a young one.. but it may be the first of a 'new' one where the old crown died, and this is the only survivor... or it could have been put in by a renter (we do that sometimes, put plants in we won't be around long enough to appreciate, just because the yard is so bare)

not a bad place, though :) mine looked WAY worse when I bought it- there wasn't a plant that didn't have a fungus infection, or something!