The Problem with ARR Progression

[Mahoukenshi]

I'm guessing you used a skip potion since all 3 of those HMs had to be completed before you could even accept the quest to kill Leviathan in the level 50 MSQ. It's a non-issue by the time it's required for the level 60 MSQ unless you skip.

It's not a big deal. They're roughly the same if not easier in difficulty than all the other 8 man Normal trials that are also part of the MSQ.

As for why SE didn't build them directly into the level 50 MSQ in the first place, I don't know. Certainly it would have been easy enough to insert the same side quest lore into the MSQ.

Ifrit,Titan and Garuda Hard were not required for Whorleater Hard (according to wiki near the end of Patch 2.2), but way later to start "Good Intentions" (beginning of Patch 2.5)