It's really not hard to mirror animations. It does not effect the character model or the clothing on the character.
Armatures control our characters which are the bones of our characters. Weight painting an setting vertex groups are what help our Armature stick to the model of the character. The biggest issue which is really like a 10mins consumption is reseting weight paints an relinking vertex groups. A quick small way to do this.

Take the Armature copy it twice. You should have 3 Armatures now just delete half of Armature 1 an the other side of Armature 2 now set it to x Axis lock an flip boom now Armature 1 should be in exact position of armature 2 do the same with Armature 2 set x Axis lock flip now Armature 2 will be in the position of armature 1 delete the 3rd one as we're prepared an it was simply for backup. Selecting Armature 2 you delete the center of the armature and anything parented at the center including the Head. Then you Parent Armature 1's spin to Armtures 2's Shoulder and Upper Leg. Now you reset the Weight Paint with 1 button click and it should automatically calculate weights. This process is not perfect so you might have to tweak it alittle bit not much though because it's normally accurate if you're good like SE with Topology ^_^. and boom that's really it's probably alot faster then 10mins