As for winter, that only goes for internal upgrades. Flew with a guy that had 16 yrs experience on jets in the caribbean, RYR took him as a DEC, he admitted to never having experienced any kind of cold weather ops.
Negative... I know a few Brazilians, and Central Americans, all experienced B737-300 to 800, hired as DECs with FR. FR would not allow them to fly PIC until they experienced on winter of operations from the right seat... at F/O's pay.