Thanks for the suggestions, could we elaborate on an example Monster to have some mathematical guidelines to try ti streamline what Is "streamlineable"?
This has set my brain onto looking at a conversion system, and so far I have come up with this (but it needs testing) -
Strength = Hit Dice x 3 (+ any modifiers)
Agility = Armour Class - 10 (for ascending) or 10 - Armour Class (for descending) , adjust for armour.
Armour = use list from monster generator in Legends and Adventurers booklet.
Base Dice for attacks = Attack bonus or Hit Dice + 3, where appropriate use agility +3 (remember success on base dice can increase damage of attack). You could also use the listed damage as a base so 1d6 damage, would be 1d6 plus attack bonus/hit dice as base attack.
Attack Damage = Use list in monster/demon generator guidelines. Attacks usually range from 1 to 2 damage, and occasionally up to 3 for particularly nasty attacks.
Test it out and let me know what you think.
I would still use the tables from the monster generator as a good guideline.
For anything that is close to a creature in Forbidden Lands, just swap out the stats or the creature. In forbidden Lands you are covered for most standard and creatures, with 3 clans of Orcs included for varying levels of aggression, and plenty of fantastical beasts, for the rest its pretty much make it up as you go.