due to MCA, there is no way to obtain vanilla baby villagers, and though people have written to the mod author on the subject, no response. so i was thinking making the egg craftable by using 4 life essence, in each corner of the table, a soul vial containing a villager in the middle, (you can still find normal villagers, though my attempt on single player to breed them led to a mca villager. go figure.) and 4 warding candles (the 4 hard to obtain items that are a part of the summoning ritual) to craft a life guardian spawn egg. it seems like the only way to fix it until the dude adds compatibility between MCA and AM2. so, the recipe as follows life essence-warding candle-life essence warding candle-soul vial-warding candle life essence-warding candle-life essence
If villager soul vials in a powered spawner produce vanilla villagers, I'd suggest the use of a villager phylactery instead, since the killing of villagers is still at least required that way. Maybe also replace 2 of the life essence with moonstone to represent the full moon requirement, and mess with automation.
if you replaced it with moonstone, it'd be almost impossible to fight the life guardian, unless you sat around doing whatever at night waiting around for the RARE chance that a moonstone meteor falls. and even if it falls, it might be difficult to locate due to it's small size. so moonstones would not be ideal, especially for those trying to get the life ward
even if it did, why would you want to get into a completely different mod just to make something? for one, why would you want to get into making 2 blocks of terrasteel from botania? personally, that was a mistake. because not everybody wants to do botania, no need to force people.
The only way I'd see the moonstone a reasonable idea was if we had the flicker habitats with the lunar tides flicker focus but yet again people will steal it because moonstone doesn't spawn in claims...