Yes you can, it should be like 1 healer per 5 ppl, or 1 healer per 4 non-healers.
So 15 ppl total in raid.
Your Tank setup is OK-ish. Best tier is Warr/Druid/Pala > Monk=>DK=>DH. Due to DK being reactive tank, but if he is good np.
Heal setup is great. Try to get shaman or priest. Shamans are great for progress (some guilds even run double resto) due to mastery and toolkit. However Holy is solid, and i wont be surprised to see discipline shine again in future. Here is player>class more important! If you can have 2 beast MW or restos bring them.
DPS: Well this will be probably the most important part, you can see stacking mages/ shadow priests/ hunters and rogues in top guilds. So if you have like 3 good mages or 3 good SPriests etc.. dont be affraid to bring them.
You can see current performance in mythic:
https://www.warcraftlogs.com/statistics/10#
And performance on mythic Xavius:
https://www.warcraftlogs.com/statistics/10#boss=1864
Some inspiration:
# DPS: 14
# Ranged: 8-10x
Mage 2-3x
Priest 2-3x
Hunter 2-3x
Lock 1x
Balance: optional
# Melee: 4-6x
Rogue 2x
Monk
Enha/Feral/War/DH/DK/Retri
# Example:
Tanks: Warrior, Pala
Healers: Pala, Druid, Monk, Shaman
Ranged: 3xMage, 2xPriest (1xHeal OS), 2xHunter, 1xLock,
Melee: 2xRogue, DK/Pala/War (Tank OS), Monk, Enha, Feral/DH
Cloth: 6
Leather: 6
Mail: 4
Plate: 4