Since the server update from silver and gold the updates for sun and moon ur referering to as alola and kalos so check ur p.r.o. Wikipedia and u will see them release some of those regions pokemon for purchases.
G.S. Ball is given and returned to sci. alexander once u find it in the ruins of alph which interlocks in 4 parts... I recently finished my g.s. ball quest at +700 hours I hope I helped u
Sci. Rey will in fact give u ur choosen bell hence water bell for suicune zap bell for raikou and lava bell for entie but its assistant davis that will allow u to switch ur choosen bell.
Lake Trio has been added entire Sinnoh Dex plus I think its legendary dex of all three lake trios that's is needed so look out for lake trio revision Uxie is my favorite to be honest
Almost to the point of boss checker in fact I just figured to exscevate most of my revival herbs 42 to be exact for most boss checkers g/l dude but I hope not
Its on ur accounts page u just have to merge the red and blue servers to the original form so u can log into the merged silver accounts or if u used yellow merge into gold