As for the next Apostle, here are my top 30 candidates ranked by likelihood, even within tiers. All are General Authority Seventies unless otherwise noted. My criteria to arrive at this list included age, length of service, leadership experience, and (to a much lesser degree) education. Full thread here.
TIER 1: Soares (P70), Christensen (P70)
TIER 2: Gong (P70), Robbins (P70), Causse (PB)
TIER 3: Kearon (P70), Gonzalez, Uceda (P70), Davies (PB), Waddell (PB)
TIER 4: Aidukaitis, Gavarret, Zeballos, Duncan, Perkins, Pieper, Pearson, Nash, Nielson, Alonso, Bennett, Cook, De Hoyos, Sitati
TIER 5: Whiting, Curtis Jr., Worthen (BYU), Maynes, Clayton (P70), Snow
TIER 6: 18 candidates. Unlikely to be selected, but have an outside chance.
TIER 7: 12 candidates. Very unlikely to be selected.
TIER 8: 37 candidates (including Henry J Eyring of BYU-Idaho). I would be shocked if anyone from this tier was selected.