I CONFIRM THAT IT WORKS! i downloaded the BLUS saves, converted them to EU, played max 2 online games and with one Sniper kill got:
Hold Your Breath: Kill 250 people using sniper rifle
Sharpshooter: Kill 500 people using sniper rifle
Supplier of Death: Kill 2000 enemies
one kill with pistol:
Close Range: Kill 250 people using pistol
one won online game:
Laurel Wreath: Win 50 rounds playing online
and FINALY:
Collector: Collect all other trophies! YESSSSSSSSSSSSSSSSSSSSSS
if anyone has problem converting to EU i will upload the converted saves.