Sorry to be wordy on this post, but here it goes:

I only recently started doing beast tribe quests. I have Vanu and Ixali at rank 7 (to be maxed in the next 7 days). The other beast tribe quests, e.g. Sahagin, Kobald, etc., are still at bare rank 1.

Thankfully, while Googl'in, I came across a general post for FFXIV that stated that once you completed Allied beast tribe quests, you auto-rank up to 8 upon completion of the last Allied quest. So, that being said, could you please add clarification to my thoughts/understandings below?

1) Max rank (as of 3.1) is 8, Allied, for each beast tribe.
2) You technically only have to reach rank 4 for each of the tribes (sans Ixali and Vanu) before you can activate the Allied quests
3) Once you rank up to 4 for the original beast tribe quests (sans Ixali), you have access to the Allied quests.
4) Once the Allied quests are COMPLETED, you will auto-rank up to level 8 for all the original beast tribe quests (sans Ixali an Vanu)