From a lore perspective, neither proposal would be appropriate. I'm pretty sure Tolkien never talked about anything -ologist in the books. That's a bit too scientific for most fantasies.
As for their purpose...
Mineralogist: Ignoring the handful of recipes that always need that random (and often rare) material from another craft, scholar is extremely self-sufficient. And with prospector to support the jeweler (again, ignoring the handful of recipes that need other crafts), that would be a second self-sufficient craft.
Archaeologist: Ditto. Again with scholar. And this time the prospector is supporting the metalsmith.
What's next? Hoplology? Scholar, prospector and weaponsmith?
And about those handfuls of recipes that need a random other craft, that is designed to improve social interaction and economy in game. This idea (like the previous one you made) will do both of those no favor at all. These are suggestions designed to promote an extremely solo form of gameplay. Since this is an MMO, these suggestions could (perhaps would?) be very bad.
R5 100 GRD Marevayave - Leader of Riddermarked For Death
R8 100 MNS Fayah/100 LM Siennah/100 HNT Dinenol/102 RK Dhurik
100 CHN Alachas/85 CPT Dinfaerien/60 BUR Dhax/35 WDN Godoric
R9 105 MNS Fayeh (alt Wilya) - Lonely Mountain Band @ Landroval