Here's some advice for your typesetter and cleaner, because I think they'd benefit greatly from it. Won't be giving advice for a redrawer, as you don't have one, and there's not really any advice I can give for PR'ing or TL'ing since that's an individual matter.
For the cleaner;
1) Use Photoshop's adjustment layers. Brightness/Contrast and Levels are important to make the text fit the bubbles fludily without creating dialogue that looks as if it was pasted over in paint. Take some time to get used to it, or try asking someone if it stumps you. The sliders aren't difficult to understand, so long as you're using copy layers to compare to the original.
2) For lower quality raws that suffer from blurring, use smart sharpening to clear up the image.
A good rule of thumb for smart sharpening is:
Amount 103% / Radius 3px / Reduce noise 10% / Remove Gaussian blur
Shadows tab: Fade amount 37% Tonal width 50% Radius 38%
For your typesetter;
1) Scale text so that it isn't consuming the entire box, and has room to be breathe while being centered.
How big exactly you make it is personal preference, but don't scale to the extreme lengths of too big or too small.
Make sure you keep track of the leading/tracking (distance between letters, distance between lines) too.
2) Use Layer Styles on floating text to add borders to floating text (text that exists without a bubble).
This can also help cover up redrawing, but don't use it as a crutch for that. Just a helpful tool, as it makes text far more legible.