The Lippert 10" Brake Hub and Drum assembly 814200 you mentioned would work just fine on a 3500lb axle as it uses the common 3500lb bearing combination of # L68149 and # L44649 but we do not carry that hub.
Instead I recommend the Dexter Trailer Hub and Drum Assembly for 3,500-lb E-Z Lube Axles - 10" Diameter - 5 on 4-1/2 # 84546UC3-EZ you mentioned as it has the same bearing combination, and will fit perfectly on your 3500lb axle.
I included a video of the # 84546UC3-EZ for you to take... view full answer...