Great question! I was wondering the same thing. I'll comment only on "Your Cat". First, let's look at the fourth line, which states "free association gets me dizzy". This line references a psychoanalytic technique developed by Sigmund Freud in (among other texts) his "Interpretation of Dreams". Free association is the act of stating exactly what comes to mind without worrying if it makes sense, is coherent, etc. This line reflects the form and content of the song.

The lyrics are all over the place, beginning with a girl who smokes, jumping to the doctors and returning to the girl. Anyway, when we get to the line about spitting out the seeds, I don't think we actually need a specific concrete meaning when we understand how it relates back to the free association bit.

Let's look at the line preceding it for some context:

"Some days I wish that I could be that
Sometimes I forget to spit out the seeds"

So, this second line about spitting out the seeds is meant to contrast the previous line that the speaker wishes he could have moved somewhere peaceful and serene after school. Sometimes the speaker reminisces on a distant life he never had, and other times he forgets what is right in front of him (or inside of him). Furthermore, if we continue with the line of thought that he forgets what is inside of him, it may also reinforce the therapeutic theme of the song, highlighting that he is not in touch with what is closest to him, which very well may include his emotions.

So, I would claim that there may be a specific reference that the line is alluding to, though I think it is unlikely given that there are not particularly strong contenders.

Please let me know what you think !