Yes it is! They are dollar store plastic bins where I get 3x for 2$. I cut out a hole so the walls of the cup touch and therefore act as a large “foot” keeping solos from topping over.
Actually yes as well! Also from the dollarstore I get small locking food storage containers. The lid locks into the base which makes them super stable with an open top.
They look like this:
The smallest one fits under the grey storage bin and catch the run-off so the plant can wick it in between waterings. I may end up cutting a series of viewing holes because if it gets too full that’s a problem.