All watch crystals that are sapphire are synthetic Sapphire, but as you say is this a euphemism for mineral glass, with some seller yes! bea carefull ask questions and read reviews from other that have bought the same watch.
Movements? what do you want to pay and to who, some dealers will sell you a clone and say it is ETA, some will sell you the ETA and it will be, the 21J asain 21.600, is a good work horse movement, nothing wrong with it all.
personaly i would go with the asian 2836, the hand size and dial feet are in the right place and size so an upgrade will be easy IF andy thing goes wrong with the clone.