You're missing some scanbobs
(It would be best to mount them all to the same sub-plate for alignment stability (not critical, but I'd strongly consider finding the space to put a scan block in there).
If you've plenty of spare change; Thorlabs are ace. // the quality is first rate + you can do the calcs to work out whichever optics you need for your design.
If not you can experiment with eBay / China optics (an ordered of magnitude cheaper), where the specs are often made up or a bonus if they are supplied.
Also: @ 1/2 wave plate: if you're good + neat, you can get away without using a mount for the WP. Quite a lot of WP's have a ground flat for angle orientation; you can experiment with the optimal angle, note it and then expertly bond it to one face of the PBS cube (UV adhesive for the win! Although I tend to use a specific low outgassing epoxy for anything that's going to be sealed.
@ Copper modules: I wouldn't stress too much about an exact transitional fit; going slightly into the clearance fit + a securing grub screw using decent thermal paste works well. (If you need any form of press / force to fit your copper modules, you loose any rotational adjustments // easy swapping out of diodes at a later date if they die.