Mixing and matching different companies components makes ZERO difference.
All trailing arms are the same, if they fit the beam, they fit the beam. Each beam made is designed to fit standard trailing arms. Obviously if you go for the reversed spindles, you'll have to have the reversed arms but still, these will fit ANY beam. I could buy ANY ballljoint dropped spindles and they would fit my balljoints regardless of my beam.
Will Transorterhaus spindles and arms fit a Frenchslammer beam =YES
Will Frenchslammer dropped spindles fit a standard balljoint = YES
Will Wagenswest dropped spindles fit a T2D beam =YES........
and so on.
All beam bearings are the same size.
Unless you start to go down the route of K&L, them mixing and matching makes NO difference at all.