Well that setter is complaining because it does not have a target. You need to drag your movement component into the graph and plug it in to the setter, because that variable exists on the movement component, not the character. (Then you should be able to set it from blueprints, i’m not sure why its not showing up in the details, but it does exists, its just being hidden from details panel for some reason).
There would not be any other way to put the original movement component in (well you could but then you would have two movement components which would not be good.)
You would either have to roll out your own custom logic (which I wouldn’t recommend because its already done for you with networking built in on the standard movement component) or just use epics default character and built up from there.