These attribution type questions — especially the names — are a little tricky. With the Jenna Sue example, “free for commercial or personal use” does not necessarily include derivatives, whereas the OFL fonts do explicitly allow derivatives. However, they also allow the license to require a name change (etc.). That kind of information *should* be packaged with the font somewhere– perhaps in the font file itself… and it would be good to figure that out before publishing any derivatives. (I haven’t looked inside the font files themselves.) If there is not any obvious location where that can be found, we’re likely in the clear to publish these.
I particularly do like the Sacramento. Bilbo, too. A fantastic source of these SIL OFL fonts (not sure if this is where you’re getting them) is Google Fonts, when you filter by “Handwriting”. Clicking through that list, I thought that the following (in addition to the ones that you already created) might be good candidates: Mrs Saint Delafield, League Script, Bad Script, Tangerine, Alex Brush, Parisienne, Delius, Qwigley, and Felipa
Probably the best way to move forward would be to add these directly to the Hershey text extension… a possible path forward _from there_ would be that we could get this updated into a future version of Inkscape itself. :) (And for that reason, we probably don’t want to label any of them as EggBot specific.)
One other consideration, which you’re probably thinking about: When possible, it is best to try and match the locations where cursive-type letters begin and end. I have an experimental optimization that I’ve been trying out, which skips the pen raise-and-lower if the pen travel distance is zero (really, below a fixed, small threshold). This makes much neater characters when the pen doesn’t have to lift between them.
It’s a tricky call what the best way to move forward on that software is– a Hershey-style font editor is a really neat idea, but I’m not sure that it’s best in Inkscape, or elsewhere– perhaps as a processing sketch that can run within a browser? There are font editing capabilities built into Inkscape now; it might be worth looking at how that process works.