Hiring has never slowed down. Training center is at max capacity. Shortage of pilots has existed for some time. Might/will get worse when 190 comes on line but by then the new MCO traing center should be able to handle many more pilots.
As far as the choice of A320 or EMB190 goes: The company has promised a choice to all new hires on which aircraft type they want. However to get the one you want you might have to wait in line for the next training slot and that will affect your seniority number. So far there seems to be no shortage of people asking for the 190 but that might be artificially high because those early folks will all be going to the left seat. Good luck!