You can already do that, you can choose what action to use when you add the item
It's not possible to wait though as it will alays hop by default
Checking it out, will keep you updated
EDIT: Been testing it for a while and it's working just fine here, hopping and filling the coal bag just fine
when inventory is full it fill the coal bag and buys more until inventory is full again before it starts banking.
I would not recommend runing it mixed as it's hard to kepe track of coal and other ores. Use only Coal or only iron ore
Restart your cleint and try running it again, make sure to check the coal bag option