I have packs. I have picks. Let's do this!
Pack 1, Pick 1
Ambuscade and Open Fire are considered by most to be the best commons (although some will argue for Unquenchable Thirst). I have Open Fire above Ambuscade, but it's close. Both Ominous Sphinx and Ifnir Deadlands are on the list of uncommons I take over the top-tier commons. Also note that Ramunap Ruins is still very good, like Ifnir Deadlands, but I have it valued just under the best commons.
Ifnir Deadlands continues to impress me. While I do think that black is the worst color, it's not by such a large margin that I avoid it. Both Ifnir Deadlands and Banewhip Punisher are uncommons that I'm very happy to first-pick, and one of the big reasons I end up in black, but I don't think I'm taking Ifnir Deadlands here.
Ominous Sphinx is pretty great. A 4/4 with flying for five is just super-solid in Limited, and the additional ability can really swing a game. I think it's very close in power level to Ifnir Deadlands, and possibly even more powerful. That, combined with the fact that blue is the best color and black is the worst, means that I think it's a pretty easy Ominous Sphinx.
Pack 1, Pick 3
The Picks So Far:
Given that we've started with pretty strong blue cards, the probability I end up in blue is high even if the color isn't open to my right (because then it should, in theory, be open to my left). The goal of this pack is to figure out what the open color from the right is to pair it with. Unfortunately this pack doesn't give much information about that, so the pick is going to be somewhat speculative.
I'm going to disregard Striped Riverwinder here. While it's the only blue card in the pack and we only have blue cards, it's just so much worse than the other options that I can't justify taking it. Even though we may not end up playing the other color we take here, I think speculating on a card has higher value.
Dauntless Aven is pretty good, but a middle-of-the-pack kind of card. I like W/U a fair amount in this format, and it's the easiest fit into a W/U deck with fliers, but given the tempo-like strategy I could play with Spellweaver Eternal, if I take a white card, Unconventional Tactics makes the most sense (and Spellweaver Eternal is a Zombie!). But Unconventional Tactics does have a low floor, and it's unclear how many Zombies I can get. While I would still take it over the Aven, I'm going to leave white alone.
What's left is a decision between Khenra Scrapper and Firebrand Archer. While Khenra Scrapper is the better card in a vacuum, I'm actually going to take Firebrand Archer here. I've said it many times here already: Hour of Devastation has a very saturated three-drop slot, especially when it comes to U/R. Given that Firebrand Archer is great in U/R and that three-drops are easy to come by, I would take the two-drop here. If my first two cards weren't blue, I think that Scrapper is enough of a better card that I would take it, but as is, I would rather optimize under the assumption that I play those cards. It's not guaranteed, but it's likely.