×You need to park only one baby near the plant, but both need to be lured off and re-lured on pressure plates at the same time(both also need to be manipulated near plant at some point, but only one needs to be left sitting there).

I parked one gel baby at 6,8. The question is, which pressure plate it ended up at?(figuring out where the other gel baby was is useful, too, I suppose)

×You're on the right track. While you lure that gel baby at 15,16, though, you need to lure the other one at 23,12 - it needs to be done almost at the same time.

Since Beethro himself is in the right side of the room(thus, near 23,12), it would be convenient to have other gel baby somewhere near Beethro.

×parking the second baby against a yellow door.