In Illustrator, you don’t have to manually erase common lines if you get pieces positioned exactly abutted (best to snap with Smart Guides), then select both pieces and press the “outline” button in the Pathfinder window. Any stroke you have will disappear, but that’s easy enough to add back, and the touching lines will then be one.
Concerning whether to share files with separate, re-arrangeable pieces or pieces already joined for material/time saving, my approach would be to offer the files in the same way I (try to) keep my own: create all the separate shapes, then duplicate that layer, lock the original & make invisible, and then do my merging on the copied second layer. This way I can go back and rearrange differently if need be.
Actually, that was my primary method before I recently learned about Deepnest. That little amazing program will take your SVG with separate pieces and algorithmically twirl those pieces around for as long as you allow in order to find common-cut arrangements that maximize savings of material, time, or a middle-ground of both, all within an outer shape of your choosing (I tend to go with 19.3"Wx10.8"H—the rough cuttable area of the GF with 1/8" material and sub-1000 speeds, which covers most of my jobs). The resulting exported SVG has overlapping common lines already taken care of for you. It can be a bit quirky with scaling down pieces in the resulting file, but so far I’ve always found the scaling amount to be uniform among all the pieces, so I just pick a random straight edge on a piece with the Direct Select tool and check its length on my original file and the Deepnest export. Then I just divide the original length by the exported length, multiple by 100, and then select everything in the Deepnest file and scale by a percentage of that number. Back to the right size. 