I've transitted in JFK between CX and AA many times. Though I've never been to the terminal LA uses, I suspect that 2:45 is more than enough, unless you encounter another snow storm.
According to the information found on the KVS Tool, the MCT is 2 hours:
[KVS Availability Tool 6.0.7/Diamond - Reference: Minimum Connection Time [MCT]: JFK/CX-LA]
Code:
DD DI ID II
STANDARD: JFK 060 075 105 120
EXCEPTIONS:
A/L DEPARR
CX JFK --- --- 180 ---
-ALL- LGA
CX --- 120 120 ---
-ALL-
**END OF DISPLAY**