Character Skeleaton & Mesh Change

Hi, I have a character mesh with a rigged skeleton that I’m trying to set up within unreal. Ive purchased some animations from the unreal marketplace that Id like to set up to my custom character. However I receive a message within the editor that there are curtain bones that are incompatible or imcomplete, I’m not very familiar with character and skeleton creation but is there a way of finding out what bones need to be changed in order for the character’s skeleton to work with the purchased animation packs within unreal.

Also the uploaded character I have appears quite small in comparison to the default model within the editor. Is there a particular measurement of the character I need to match the default character mesh. I appreciate any assistance regarding this matter and hope to find a resolution to have the character working within the editor. Thank You