A few thoughts:
Ep. 1 - Alvida and Shell Town. Introduce Nami, Zoro joins
Ep. 2 - Buggy. Nami joins. Arlong is set-up.
Ep. 3 - Gaimon and Luffy's Backstory. Use Yasopp to introduce Usopp. (*Perhaps Buggy's story and Coby's story)
Ep. 4 - Syrup. Usopp joins.
Ep. 5 - Baratie Part 1. Sanji introduced.
Ep. 6 - End of Baratie. Nami leaves. Sanji joins.
Ep. 7 - Act 1 and first half of Act 2 of Arlong
Ep. 8 - Second half of Act 2 and Act 3 of Arlong.
Ep. 9 - Epilogue of Arlong. Nami rejoins, arrive in Loguetown.
Ep. 10 - Loguetown and Red Line
Putting in arch plot:
Ep. 1-3 Act 1 of East Blue Saga
Ep. 4-6 1st Half of Act 2, with Nami leaving being the Mid-Point
Ep. 7-9 2nd Half of Act 2, with deciding to go to the grand line as the Climax.
Ep. 10 Act 3
Works nice. I don't think they'll outright skip Gaimon, since for futureproofing they probably wouldn't do anything that other adaptations (4kids) dug themselves into. Cut it down, sure. But not skipping. Luffy's backstory capping the first act also makes sense, and it's short enough that Gaimon could be used as the framing device for it. Nami should leave by either episode 5 or 6, because you need that "oh shit" moment mid-season, and the earlier arlong (aka the arc that everyone says is where the story picks up) is set up the better.
There's no reason to not have all of East Blue happen in one season. A faithful adaptation =/= a good adaptation. There's no reason why a story like Buggy's can't happen in an episode. The same with Usopp. The information you need from those stories are simple enough (Buggy, Nami, Usopp. That's it), and their themes aren't complex enough to demand anything else than an episode. That leaves much more room to beef up Baratie (which is a perfect mid-season story), and heighten the stakes for Arlong. Everything "taken out" of the previous stories could be put in Baratie/Arlong instead, as far as any thematic aspects or character development.
*As far as cover stories, they could either spend an episode/place them in lighter episodes; or, more interestingly, adapt them as post-credits scenes. That could easily look like:
Ep. 1-4: Colby's story
Ep. 5-9: Buggy's story
Otherwise, they're skipped, or made into shorts.