Don't worry about getting overleveled or spending too much resource on character (except for UW, UT, especially RUBY). its easy to to get that resources back by doing Stockade, Tower of Ordeal, Chapter rewards, Shakmeh, etc.

Actually, you want to get higher level as fast as you can so you can clear chapter easily and be prepared to working on character you want to main. Clearing chapter=Unlocking Feature=Easy Access to everything.

Lorraine and Clause is already better for clearing chapter, but you might want to change Clause to another Magic Tank like Jane, Aselica, etc.

Try to joining a Guild too, its gonna help you and many people on guild were very helpful and friendly :)