Make a custom function to fire the montages.
Allow that custom function to toggle on/off whaveter abp variables you need to toggle off.
For the crouched issue, you simplly toggle crouched off, then play the montage.
The character won’t return to a crouched state (or more appropriately in your scenario it never left that state) afterwards.
Additionally, for death you really want all ABP states to transition to a death state whith a one directional transition, so that it is not possible to hack out of your death state.
Takes a bit of linking work, but saves you from future issues.