Nice job Abeysaurus! Perhaps you could just use placeholder animations or “stills” in the release with video instructions on how to substitute them with Mixamo or similar animations? For some people (as in my case), the rig they’re using may not be retargetable to the UE4 Mannequin, so custom animations for their specific rig would be needed anyway. Also, unless the end product is for sure only going to be a stylized character, it may be time-consuming to match the realism of mocap animations that may be available. Of course, that all depends on how comprehensive you want the Marketplace pack to be. I’m personally more interested in the (excessively commented!) Blueprint tech behind climb systems.
One thing that you may want to implement (which I was adding into my own system) is the ability to detect and grab ledges that are directly above each other. In other words, if you had a stack of cubes (with space between each) and the character jumped beside it, he would be able to grab the ledge that was nearest the peak of his jump. When falling off the stack, he would be able to detect and grab each descending ledge each time he lets go. I believe I used a multi-sphere trace by channel sweeping down for this. This is not strictly necessary, but for tower-like edifices with multiple window openings that you could only reach by dropping down from window to window it would be useful.