The Eradicator Squad Datasheet was created using the Aggressor Squad datasheet.

Melta Rifles were built using the Meltagun profile from the Ironclad Dreadnought profile.

Heavy Melta Rifles were a little tricky, since they are just Melta Rifles that are Heavy and do more damage. We decided to make improve the SAT from 7+ to 5+. This makes Multi-Meltas still better, since they have 1 point better SAP and SAT

The additional Multi Meltas presented a bit of a challenge. The profile should probably be "pick 3/6 weapons, all have to be rifles or heavy rifles, except 1/2 can be multi meltas", but that is pretty complex for an Apocalypse datasheet. In the end, we decided to just make it so that the Multi-Meltas are in addition to the Melta Rifles, and cost an additional PL. One dude in the squad is dual wielding like a badass.

For Power Level, we made them cost 1 PL more than Aggressors, which matches the changes in the Jan 2021 FAQ.

Total Obliteration

This was a little tricky, since "Advance" means very different things in 9e and Apocalypse. In the end, we tied Total Obliteration to the Aimed Fire order - technically a small nerf compared to 9e, but its not like Eradicators are gonna suffer that much from a small nerf:

"When this unit's detachment carries out the Aimed Fire order and this unit makes a Shoot action, double it's Attacks characteristic and the Attacks Characteristic of any Multi-meltas it is equipped with for that action."