1. What sense should FMCB have, if that would be the case?
It doesn't need a Modchip at all, so it also doesn't rely on any DEV.-Mode.
The bast way to run FMCB with a modchip is, to simply turn off the mod, or turn it to PS1-Mode if no disabeling-option is available.
(Magic 3 was holding Reset for 3Seconds, if I remember correctly.)
So,... No. (DEV.-Mode isn't necessary.)
2. If your mod isn't compatible and couldn't be disabled, this might work.
3. It is embedded in the installer. mcid-generation is a necessary step, to create a valid encrypted file on mc (which is necessary to use Sonys Upgrade-Feature).
4. There isn't any flasher in newer Versions than 1.1
No you couldn't copy&paste installed fmcb-files.
The "update-file" is specifically encrypted to your mc.
5. Those are for providing compatibility with old PS2-Models of the 1x-k-Series (I couldn't remember, if it was only for 10k, or also 15k and 18k-Models. k = thousand. e.g. SCPH 18001 is an 18k-model of jap-region)
7. No. This is only to load patched&burned DVD(V)-Backups of PS2-Games.
9. These are two complete different projects.
A modified HD-Project was used in early FMCB-Version (where it doesn't have this name), to dump and flash mc-images from and to your mc.
10. No. As long as you don't get rude (when someone tries to help ya. ).
Btw.: I think your post is very good structured and readable.
You collect your questions and give them digits, which make it easy to follow all your questions and answer them correctly.
PS2 V7/DMS3 V2 (FW:2.4b7); Seagate Baracuda 200GB
PS2 V7/CC1.0 (FW:34 hacked v2 BM:2.1.6); Maxtor DiamondMAX9 PLUS 160GB
PS2 SCPH-30004R; NoMod+NoLaser
3xSony MC 8MB
MAX/Datel 16MB with Boot-CD
Custom FMCB 1.8b+ Beta-Build, my AIO 0.5, Sony&xRhino-Linux