Corpse Life Calculation Question - "Increased Corpse Life" + Spectres + Desecrate

Hi! I have a few mechanics questions around corpse life, spectres and desecrate.

I have done some research into how spectres affect the corpse pool (namely looking at this badger video[0] and some specific mob data in poedb, eg lithomancer[1]).

Some things that weren't really clear to me is how corpse life is calculated. My understanding is:

1. Monsters have a set base life based on level (values here[2]).
2. Each different monster has it's own "life" multiplier (eg Lithomancer's have "800% increased maximum life?") which is then applied to the monster.
3. There are a few "Corpses you Spawn have x% increased Maximum Life" mods on the tree (primarily the "Corpse Pact" Necromancer notable).


So my questions are:

1. Does the "Corpses you Spawn have x% increased Maximum Life" apply in the same layer as the base monster calculation or is it separate? For example if a player have +50% corpse life from corpse pact would a Lithomancer I spawn from desecrate have:

+850% life or +800% life (base) * 1.5 (50% corpse life)

eg 8.5x base life or 12x base life

(Now that I am looking at this I have a feeling that it is 8.5x instead of 12x :( - since I am doing corpse explosion it means this is not much effect but wanted to check).

2. Does the level of a spectre that is included in the corpse pool affect the level of the corpse that is generated with desecrate, or are they separate mechanics?

Eg I know that desecrate can spawn corpses up to level 100, and it is limited by the zone level - eg for most bosses like sirus this would be a corpse level of 84. If a spectre is level 72 will the corpse still be level 82 in a ilvl 84 zone.

Links:

[0]: https://youtu.be/hayhnBg6gOk
[1]: https://poedb.tw/us/Lithomancer
[2]: https://pathofexile.fandom.com/wiki/Monster_level