According Playstation Official Magazine, March 28 2014 you will no longer able to use the online features of the following games:
- Resistance: Fall of Man
- Resistance 2
- Resistance 3
This will make multiplayer play after the date impossible so the online trophies un-achievable.
I myself own the first two games but I think it will be cutting it close to start getting the online trophies for the 2nd one now.
However, there are boosting sessions going on now for people willing to try: