Here are the remaining issues to be decided, in descending order of magnitude.
Everyday third-base: Jake Lamb vs. Yasmany Tomas
You would be very hard-pushed to find fault with Jake Lamb's performance this spring. He has batted .355, shown decent power, with 10 of his 22 hits being for extra-bases, and played solid defense. Coming in to spring, Tony La Russa said of Lamb, "His talent is oozing," and while I'd recommend seeing a specialist about that, Jake seems to have rebuilt his stock after a disappointing debut season where he hit .230 and struck out in 28% of his PAs. Tomas, meanwhile, has endured an often painful education as to why third is called "the hot corner" and his hitting numbers have been no more than okay: .273/.324/.439, with 15 strikeouts to three walks.
With Chip Hale saying "Jake Lamb has honestly outplayed him at third," the consensus appears to be that Lamb, rather than Tomas, will be the everyday starter. It like;y helps Lamb is left-handed - switch-hitting Cliff Pennington is the only other semi-lefty infielder on the 40-man roster. As we'll see, this doesn't necessarily mean there won't be room for Tomas, and Hale added, "There are other ways for Yasmany to make the team." But I do wonder if his development would be better served by playing every day in Reno, especially if we are intent on continuing to use Tomas at third. Since Aaron Hill is on the bench too, that would also eat into Yasmany's playing time.
Final bullpen spot: Enrique Burgos, Andrew Chafin, Vidal Nuno or Robbie Ray
"One of these things is not like the others, One of these things just doesn't belong, Can you tell which thing is not like the others. By the time I finish my song?" That would be Enrique Burgos, who is the only right-hander, and the only 'true' reliever, with the others all being southpaws, and converted starters. That may help give Burgos an edge. While it might not be a bad idea, given our rotation, to have multiple long relievers, the team already has Randall Delgado and Daniel Hudson in the bullpen. They should both be capable of working multiple innings if needed, so do we need a third such arm down there?
On the other hand, Burgos hasn't played above A-ball and, while his spring numbers were impressive, that's still a heck of a jump. Going with him would also leave Oliver Perez as the only left-hander on the entire pitching staff, starter or reliever. I suspect we will go with one of the lefties - and the decision may be a process of elimination, based on picking the one they don't want to be stretched out as a starter with the Aces. The departure of Trevor Cahill and subsequent promotion of Archie Bradley probably moves the Robbie Ray up the depth chart, and if so, it's probably close to a toss-up between Chafin and Nuño.
Backup catcher: Gerald Laird vs. the World
In the wake of the Peter O'Brien disappointment, Tuffy Gosewisch has been anointed as the "everyday starter". However, the issue of who will be his backup remains open. Veteran Gerald Laird appears to be the front-runner, but playing-time in spring was fairly evenly divided. Gosewisch got most AB (42), but after O'Brien (32), there wasn't much to separate Jordan Pacheco (30, albeit mostly at other positions), Gerald Laird (29) and Blake Lalli (25). Also worth remembering, the back-up spot is likely to be a temporary one, until Rule 5 pick Oscar Hernandez returns from his broken hand, as a roster spot will need to be found for him.
The rest of the bench: Pick five
Some names appear to be inked in. As discussed above, there'll be at least one backup catcher - Hale said it would be difficult to carry a second one - while Ender Inciarte, Cody Ross and Cliff Pennington all appear virtually to be assured of spots. That leaves only one spot left, and if Hill isn't dealt away, it would have to be his. This initially appears to mean no spot for Yasmany Tomas. However, if the Diamondbacks wanted to go that route, and Aaron is still here, then Inciarte could be optioned to Reno, and Tomas can make the roster, to be used as both a fourth/fifth outfielder and as a left-handed backup at third-base.
My instinct at this point, however, is Tomas starting off in the minors, and a bench of Laird, Inciarte, Ross, Pennington and Hill. That's okay, but it doesn't have any left-handed power, and there's no-one who can spell Goldie at first - yeah, there's the Mark Trumbo route, though it isn't ideal, since they're both right-handed Now, we're probably expecting Paul to start at least 150 games, probably more [last year, he started 108 of the 110 up until the Pirates broke him]. But it would be nice to have an Eric Chavez type, who could provide some lefty pop off the bench and give Goldschmidt a (very) occasional day-off to get him through the season.
Overall, I've been favorably impressed with the moves in the past couple of days. While I still have issues with the Cahill trade (specifically, the timing), it is in line with an organizational philosophy of giving young prospects every chance this season, also illustrated by the decision to go with a middle-infield of Nick Ahmed and Chris Owings. It would be unrealistic to expect all of this to work off the bat, and I still expect the Opening Day roster to be radically different from the one which finishes the season. But it should certainly be more fun to see young, cheap players (hopefully) develop than watch established ones flounder. I had my fill of the latter in 2014, thank you....