Attempting to get caught up!
The main referencing here is, of course Indigenous Australian myth. Uluru is the Indigenous name for the landmark named Ayres Rock in 1873. In 1993 the original name was reintroduced, with the official name being Ayres Rock/Uluru, and then reversed to Uluru/Ayres Rock in 2002. The creation myth shown here doesn't appear to be based on Indigenous legends though.
Carlton Marvell has some elements of Mar-Vell, though back in the days of the WEF, Ellis also confirmed that Adam Strange was an influence. He bears similarities with any number of explorer of the unknown characters though. In more of Planetary's deconstruction, Snow notes that he and Marvell saw horrible things through the portal, referencing the danger-filled worlds explorers always face in those stories.
There's a lot of continuity in the front half of the book. Snow visits Ambrose's widow and child (Whom we saw shortly after birth in the flashbacks in issue 9). The way snow talks to Angela show that even at 100 years old, he's very good at talking to kids, suggesting he has experience raising some. Recall as well that in issue 12 he spoke of changing Jakita's nappies.
It contrasts sharply with the next sequence, wherein he calls Jim Wilder with an intent towards talking about Anna Hark. He's been interested in Hark since he spoke with John Stone, and he's gathering information now. Note my theory on how Snow deals with his opponents - gather intel, find the upper hand, and then strike. He's going after Hark here.
Snow's meeting with Brass is another bookend moment in the book. This is the first time Snow's seen Brass since issue 5, and they're back on the same hillside. Here Brass is just answering questions, confirming his circuitous relationship with 1930's and 1940's Planetary. There's a reference to the Hidden City of Opak-Re here, and a suggestion of a link to Jakita.
The first half of the book is building up to Snow's first engagement with the Four since his memory returned. Interestingly, the title page is the halfway point in the book, and the start of the direct confrontation between Planetary and the Four.
There's some nice moments in the back half - I love Snow and Drums' back and forth. Drums has not regained the respectful tone he had with Snow in issue 14, though Snow is treating him like an equal in a way he hasn't in the past. "You've been listening to me"/"Don't expect me to admit it" is banter, not insults.
The actual conflict with the Four is perfunctory and is quite tension-light, but Cassaday's art elevates it by virtue of the spectacular scale he imparts. The important thing here is the suggestion that Snow has changed his strategy - he's made a bold move to confirm 100% that he's back and gunning for them, but he hasn't gone for a decapitation strike yet.