Late 2014 sounds implausible, the Mini was the first Mac to get the M1, and was updated timely with the M2 while adding an M2 Pro option, is normal for Apple to spread out launches so chip yields are not a problem and to focus attention on higher-end models and options, but I don't see why both the MBA and the Mac Mini wouldn't be updated in March as rumored.
M3 MBP demand would be fully realized and normalized by then, and a surplus of M3 chips will be available for both lines to be updated.
Late 2014 would be the start of the M4 production phase according to rumors.
M3 MBP demand would be fully realized and normalized by then, and a surplus of M3 chips will be available for both lines to be updated.
Late 2014 would be the start of the M4 production phase according to rumors.