you might have to do some testing for yourself to find out what is what, but from what I understand, anything that increases the MP & MP Regen and is then converted to HP & HP Regen with Blood Magic is still considered separate, to a certain degree, from HP & HP Regen, for the purposes of not doubling up on bonuses.
so the 5k MP Regen is increased +125% by Cosmic Power, and then increased again by Druidic for another +125%, and then switched my Blood Magic to HP Regen to be added to any HP Regen you already have.
Druidic also increases HP Regen by +125%, but only the HP Regen that is available before the MP Regen is added to it.
this is how I see it working just by how it is written in the descriptions, but it is possible that your testing, or a Mod or Dev, might have better information than my little theory.