All 3 quests that finish this chain:
The Arcway: Long Buried Knowledge -> Mythic Dungeon: [zone=7855]
The Arcway: Opening the Arcway -> Mythic Dungeon: [zone=7855]
Court of Stars: Beware the Fury of a Patient Elf -> Mythic Dungeon:[zone=8079]
Are inside Mythic Dungeons. There's no LFD for mythics, you will have to search for a pre-made or make your own group.
If you received these quests, it means you are unlocked for the dungeon and you can enter. Most likely, the actual 'lock' for the dungeon is the previous quest in the chain.
UPDATE: It has been confirmed by several players in the forums that these quests CAN BE SKIPPED if you are only worried in getting Good Suramaritan that is also part of Broken Isles Pathfinder, Part One that will (along with part 2) allow you to fly in Legion.
These just give rep and rewards but are *not* requirements for that section of the Suramar loremaster.
In order to get Good Suramaritan after this, you need to:
- Do the quest The Stuff of Dreams that is inside the raid [zone=8026]. You can do that raid and loot the item/kill Xavius in any difficulty. So you can wait until LFR wings are open and progress there. This one in particular belongs to "A growing crisis" within Good Suramaritan.
- Get exalted with Nightfallen. Once exalted, you will get "A Change of Seasons" within Good Suramaritan.