Not trying to burst a bubble but I do not thing we will receive memory drives from all types. It would make sense that the memory drives are included in Awakening Hero. However
Peeping Red Card is number 47/50.
Psychic Memory is 48/50 and
Fighting Memory is 49/50. Considering that we know that
Gladion is number 50/50 and
Silvally GX itself is number 46/50 there is no more room left for the other memory drives in this sub-set.
We might get some memory drives in GX Battle Boost along with alternate art cards for Ultra Beasts and other cards released thus far in addition to the missing three Ultra Beast GX. If so I assume that we get Fire Memory and posibly Lightning Energy. The main rationale behind this assumption is that this would allow Silvally GX to hit all the Ultra Beasts for weakness. Psychic Memory allows Silvally to hit Buzzwole GX and Nihilego GX for weakness. Fighting Memory enables him to hit Guzzlord GX and Xurkitree GX for weakness, while Fire Memory would presumeably allow Silvally GX to hit Kartana GX and Pheomosa GX for weakness. Assuming that Celesteela GX is Flying Lighting Memory would allow Silvally GX to hit the seventh Ultra Beast for weakness too. It would make sense from a storyline perspective.
If these assumptions hold true we should approach Silvally GX by simultaneously taking into account its ability and the memory drives. You would preferably run him with some basic non-GX attackers to cover two to three of the dominant weaknesses in the local meta. Registeel cover Metal weakness while Regice or Palkia from Shinning Legends covers water weakness. Select a third attacker that can utilize Double Colorless Energy and cover the fourth dominant weakness with a memory drive. Since Silvally GX and Registeel both accelerate to the bench and the deck could use Max Elixir a four corners version centered around Silvally GX could be indeed viable even without memory drives for all types.