yes you can use fontMake or ufo2ft, you just have to install it locally for the python3.6 (this is the embedded python in DrawBot)
If you dont have python3.6 installed, you need to get it from https://www.python.org/downloads/.
and install fontMake and/or ufo2ft with pip3.6 for py3.6
good luck!
ufo2fdk needs some basic font info settings like descender, xHeight, ascender, capHeight, unitsPerEm
# some default example values
font.info.descender=-250
font.info.xHeight=500
font.info.ascender=750
font.info.capHeight=750
font.info.unitsPerEm=1000
Im pushing you to figure it out by yourself first 
see the documentation and the source of ufo2fdk
and see documentation of fontMake
font.generate is RoboFont method and is not available inside DrawBot.
However with ufo2fdk (which is embedded into DrawBot) you must be able to generate binaries (you will need to install FDK locally)
or install fontMake and build a compiled font from a ufo.
good luck!!!
so far there is no support for any kind of forms.
A contour object has a contour.clockwise which is a boolean indicating what the direction is. Hope this helps you out.
a segment always represent a line with a single point and a bezier curve with 3 points (2 off curves and one oncurve) this is the behaviour in RoboFab ever since...
A contour object has an attribute contour.open which is a bool indicating a contour should use closePath or endPath for open paths.
oh, there is indeed no progress callback on saveImage(..)
Doing some googling on 'progress' and 'ffmpeg' does not results in a clear solution.
DrawBot has a small wrapper around ffmpeg to generate movies: see https://github.com/typemytype/drawbot/blob/master/drawBot/context/tools/mp4Tools.py
there are plenty of options to have some sort of process bar that gets updated for each frame:
see https://stackoverflow.com/questions/3173320/text-progress-bar-in-the-console#
If this doesn't makes sense I can narrow it down to an simpler example!
good luck!
you can use a clipPath(path) to clip a drawing inside a given bezierPath: see http://www.drawbot.com/content/shapes/drawingPath.html#drawBot.clipPath