Fuel shouldn't be a problem.
Go into the hold if the wx system is moving through reasonably quickly. You don't have to hold where it says on the chart although that makes things tidy
You can hold where ever it's safe from wx (and clear of restricted airspace, terrain etc)
Yes, there is an alternative and that is the divert. Holding and diverts to the alternate(s) are planned on the ground
and reviewed when airborne. As you've noticed, things change.
Slot on the ground won't be a drama, if the wx's stuffing you up, it's stuffing every one up.
Penetrating an active cell isn't the wisest thing to do. The least you'll do is spill the drinks and spook some of the pax. The worst you'll do is much worse....
