I would keep Melvin Gordon, TY and AP. I don’t know what pick you will have in the draft, so I’ll make some assumptions…
No need to keep Julio, you could still land someone big in the first round. Judging by the fact that you went for Julio RD1 I guess you will have one of the first 4 picks, so you could still get someone comparable to Julio’s projections. Having said that, you would be having one of the last picks of the 2nd round so TY is a great fit for that spot.
Gordon’s ADP right now positions him in 1st or early 2nd, so that one is an obvious pick (plus, he will continue to be the featured back in LAC).
AP’s value in round 18th is the best in my opinion. Very little downside, and a loooot of upside. You get to keep your early round picks for some other RB like Crowell, Lynch, Fournette, and can still target Mark Ingram/Kamara if you feel like it.