Brake assemblies are available at most any online trailer parts suppliers in bothj 7 and 10 inch....Problem is axle.... Most axles that can use brakes have a flange welded to it to bolt backing plates to.....

The next question is whether the hubs (of drum) for the electric brake system will fit the existing HF axle (probably not), then its the wheels (clearance diameter of wheel to go over brake drum, and lug pattern) .....
Best plan would probably consider getting new axles custom made to correct width equipped with brakes and uses a acceptable wheel bolt pattern..... Purchasing as a set can sometimes be more expensive but less frustration as its all designed and fitted together as a kit, trying to piece part something together and finding out next item does not fit last item purchases or the they don't make something you need because you ready fitted a item to project that only accepts a part the does not work well with whole concept of rebuild.... Them there is issue of room for new size wheels and tires and fenders....
Not a impossible task, just need some real though and engineered on paper long before you purchase first parts...
Dale
Lives his life vicariously through his own self.
Any statement made by me are strictly my own opinion.
You are free to ignore anything I say if you do not agree.
