definitely not cannabis but not sure re Basil. They look very familiar.
you propagate wheat by seed, let it seed.
Wheat is quite decorative. Some of it comes from bird seed.
yes it is KOG
I wouldn't bother, the containers will be lighter if you dump the contents. If you wanted to keep the Lysimachia you could put a small piece in a small pot
more like Solanum dulcamara, which is known as Bittersweet.
Climbing hydrangeas aren't plants for a pot against a south facing wall. Better in the ground but if that's not possible, get it out of the sun. Mine does very well in more or less complete shade
a Solanum, one of the nightshades
I'm in no position to criticise anyone else's photography pp