Needless to say I don't think he'd do much better than Delaney at this point, Ojeda may end up doing better than him.
My hunch is that Castro is more likely than Ojeda to end up as enough of a realist to drop out before Iowa when it's clear that he's going nowhere. Therefore, Ojeda might be more likely to get more votes than Castro simply because Castro is more likely to drop out before people start voting.
And Delaney's independently wealthy, so his campaign going broke is less of a worry. And so again, he's probably more likely than Castro to still be in the race when the voting starts.
That said, I think Castro is more likely than either of them to be invited to the first debate. Honestly, if you only need something like 2% or whatever in the polls to be invited to the debate, then just having a Latino last name might get you most of the way there.