Make changes to creatures.xml file

Is there a way to change the creatures values for the costs in resources?
It's possible for gold, but not for other resources.

Ex:

Change the Titan's cost from 2 Gems to 4 Gems.

Also, the special capacities of creatures are not all accessible?

Ex:

20% chance to Paralyze creatures for the Cyclops,
Immunity to spells,
Death area effect (7 hexes) for the Liche,
Transformation of creatures (decimated creatures becomes ghosts for the Ghost),
Morale malus for the enemy troops for the Bone Dragon,
etc.,
etc.,
etc.

Not currently. This information is stored elsewhere; I'd need to check, but I believe the game is not currently built to allow lower tier creatures to cost resources.