You should look into retargeting. Whether you use the same armature or different ones you will need to be able to retarget animations between skeletons. Although if I’m not mistaken you can make the characters all on the same armature and import them to the same skeleton.
You would want to blend by Boolean inside the animation blueprint. Set a bool inside of the character (bow equipped? Or sword equipped?). Cast inside of the animation blueprint to the character and pull out those booleans and make the same Boolean variable inside of the animation blueprint and have them set by the character ones.
Yes that would definitely help. Most cases I always have to adjust the starting pose of bones with the engine (using the keyframe) inside the animation. Make sure to follow retargeting guides because it’s always good to do things such as the same pose between characters before retargeting.