I have Lycanites mod installed. And It seems I cannot use abilities with them. For example: cannot fly with flying creatures, cannot climb up walls with spider creatures. Is this a problem? This is also happening with every mob mod I have installed, such as Exotic birds, Mowzies Mobs, etc. The flying mobs cannot fly when I morph into them, which is my biggest concern.

It's not supported by default, but you can configure modded mobs to use the same abilities that vanilla mobs use. Check out the wiki.

Oh, alright. Thanks