If Ange is our NP, I think June Mar is not indispensable. Otherwise, I have to agree that we might need him, although we need to watch his age (he was born November 1989, making him 34 now, 37 by the 2027 WC, and 38 by the 2028 Olympics).
As for the four, the PBA does not have a big four. They have Troy, yes, but he's a poor FIBA player. Like I said, they have ZERO reliable FIBA-eligible options at 4 outside of Brownlee and the recently-retired Japeth. If our NP occupies the 1, 2, or 3 slots, I think we need one of Carl or Balti as an extra body at 4. And by the way, Malonzo provides shooting, help defense, and some perimeter D. Carl provides post scoring, shot creation, post defense, and size at the 4. Different skillsets, but we need Malonzo's defense at 3 and Carl's size at 4 (if Brownlee's not the NP).
Oftana is a reliable defender and hustles for boards, but he's not the shooter Parks is. Name a reliable FIBA-eligible shooter in the PBA not named Terrence Romeo (who's 31) and Marcio Lassiter (who's 36). Heck, Pogoy, who had a good outing last WC, is 31. Our best shooters are not in the PBA. They're Parks and Heading.
And lastly, a lot of our reliable PBA players are aging or old. Castro's 37, Marcio's 36, Abueva's 35, June Mar's 34, Newsome's 33, Terrence is 31, Scottie is 30, Perez is 30. We need youth. Good thing the PBA has Navarro, Oftana, and Malonzo as good 26-27yo players. While Schonny (25), Tuffin (26), and maybe Mamuyac (24) can be reliable, we need to test them in FIBA first, and except for Mamu, they're not that young. The overseas guys provide the youth we need. Carl's 22, Kai's 21, AJ's 23, SJ's 24, RJ's 24. We need to be selective in which 30+-year-olds to retain.