Emberwake prolif and crit behavior

I can't find any reliable info on how exactly Emberwake http://pathofexile.gamepedia.com/Emberwake works.

Let's say i have flameblast with 100% chance to ignite and elemental proliferation.
I now hit two enmies that stand right next to each other with a flameblast crit.

How many burn effects are dealing damage to each of these two enemies given no other sources of burn? 1, 2 or 4?

1: default ignite and crit ignite do not roll and apply individually; prolif does not stack.
2: you can ignite an enemy twice per crit.
2': prolif stacks
4: prolif stacks and ignite can potentially be applied twice.

testing this is difficult and i don't have any test characters left this season :P

2': Prolif will stack.

You can either ignite or not ignite with a hit, crit and chance to ignite are just two ways of applying it.

To extend raics' answer a bit. When u crit, u have 100% chance to ignite. It is not some separate effect from normal chance to ignite. Meaning, u can not proc crit and chance to ignite on the same hit. U either crit(will ignite) or have normal hit with ignite or normal hit without ignite.

And some math example to extend a bit more. U have 50% crit chance and 50% chance to ignite. Than u will not have 100% chance to ignite, but 75%. They stack multiplicatively with each other. Also meaning, the more crit u have, the worse chance to ignite stat gets.

Thanks for the answers. As a follow up question: does the prolif damage modifier only apply to the initial hit or to the burn as well(and thus twice for burn) ?

Only ones for the direct hit, as far as i know.