Any decent machine Shop should be able to re-drill your rear axles to accommodate a 5 lug pattern, the same with your drums. As long as the center hole in your wheel is the same size you should have no problems.
I had the idea years ago to make a 5 bolt truck. Sent rear axles to Moser whose tech told us that after welding up old holes, material too hard to properly re-drill. Sent them to Jerry (HRL0 and he tried for awhile and I think finally decided this was a correct statement. We abandoned the project. In my opinion, the custom new axle approach may be best. I am going to learn to live with 6 lugs.
