Do you have gold medals on every mission/strangers as well as gold medals with all three characters in flight school/shooting range/tennis/golf/darts/races/etc?
I have 0 bronze, everything is silver/gold. No cheats used, I have well over the 70 requirement for gold, done all flight schools with michael and frankyln, shooting with all 3 chars, tennis, gold in all the triathalons (even the half hour long one that kills your finger). Robbed all the places I know of, talked to all the blue dot players. Got all the strippers numbers, used the ign guide even to get all the prostitutes while I was trying to lie with 9 women in a week as michael. Did every single stunt jump/knifeflight/under the bridge/letter scrap/ufo part/nuke waste (not just ones required for 100%) Have all properties bought, pretty sure I bought every item of clothes, all gun upgrades, etcetcetc. Still have like 1.5bil on each char.
For trophies the only one I'm missing in single player is kifflom, because that mission is broke for me. Waiting on R* support to hopefully get me fixed.
I really doubt they would make a requirement like that, 1 you cant see these stats in game - only on social club, 2 - 100% isn't possible without collectors, 3 - some random events you can miss (simeon) or are unable to be completed.