2 - in the overview in the smartphone app (More → Logic) the variables are sorted alphabetically, probably also numerically.
3 - maybe it helps to use an own system, e.g. B_ for boolean, N_ for numeric and S_ for variables with strings, or the name of the room, or something similar…
4 - there is a search function.
5 - please see point 1.
7 - Unfortunately, the name of the variables are only partially automatically updated. Variables inserted via tags are automatically updated. Variables inserted via dropdown are not automatically updated. You have to update them manually in the flows.
Maybe it can be done via a homey script, but I don’t know.
8 - please see point 1.