licking your diff probably isn't a good idea, your tongue might get pinched

and yes you should be able to add an e-locker down the road

 

Certainly possible to add front/rear diff lockers any time.

 

I added a PowerTrax locking diff "lunchbox" to my 3rd Gen T100; they fit inside the housing you already have, and take less space inside than the original spider gears. Theres no interference to stop you from adding a E locker later.