Put ALL vanguard familiars into one event so that you only have to use any of the units with a vanguard familiar in order to obtain ANY vanguard familiar including their own.
I feel like that would make it a lot easier and less of a chore, without removing the time gate you guys love so much (please just remove the time gate)
I understand that it removes the concept of having to use that specific unit in order obtain their vanguard familiar, however that should stay for when the VF is first released. Afterwards, it should be sent into that single "Vanguard Familiar" event where the quests are to use any of those units and get currency to buy any of the vanguard familiars.
TL;DR -
Put all vanguard familiars into one event so the currency used to buy them isn't separated.