For both Fracturing Gust and End Hostilities, only Hyena Umbra will get destroyed.
Both
Destroy all Enchantments.
and
Destroy all creatures and all permanents attached to creatures.
are effectively
Destroy Boon Satyr and Hyena Umbra.
There's only one instruction to destroy, so everything is destroyed simultaneously.
The Umbra's ability modifies that instruction
Remove all damage from Boon Satyr and destroy Hyena Umbra and Hyena Umbra.
It's impossible for the effect to destroy Hyena Umbra twice, so it only does it once[CR 400.6][1].
Remove all damage from Boon Satyr and destroy Hyena Umbra.
So, you remove all damage from Boon Satyr and destroy Hyena Umbra[2].
This is supported by a ruling on the Umbras
If a spell or ability (such as Planar Cleansing) would destroy both an Aura with totem armor and the permanent it's enchanting at the same time, totem armor's effect will save the enchanted permanent from being destroyed. Instead, the spell or ability will destroy the Aura in two different ways at the same time, but the result is the same as destroying it once.
This means that only a single regeneration shield is needed to save Hyena Umbra.
Only one Enchantment was destroyed, so you gain two life from the remainder of Fracturing Gust's ability.