I don't think "Mystery Plant #5" is an asparagus fern. Not one I've ever seen before, anyway. It looks very much like a weed that grows in my yard. I have no idea what the name of it is. I just call it "sticky weed," because it clings to your clothing when you pull it up.
IIRC, it eventually produces tiny little flowers. I'm not sure that's what is in the pic, just looks like it to me.
I'd probably leave #4 to see what it does. Could be something nice, or it could be deadly nightshade. To early to tell for certain.
#3 reminds me of a chrysanthemum, but I have no idea whether or not that's what it actually is. This is one I'd wait and see on.
#2 also reminds me of a weed I get around here. It produces spikes of lavender flowers. Some would probably call it a wildflower and let it be, but it really invades my yard badly if I fail to pull 90% of them up.
I've never seen anything like the one titled "Mystery Plant."
I think you should just let them grow and see if you like them as they mature. Except for #5. If you touch it and it wants to stick to your clothes, I highly recommend that you pull the stuff.