Is there a way to generate the fonts without decomposing the components?
What for? Components in TT-based fonts are kept. PS-based fonts should not have components.
Sometimes it can be interesting to bend the rules a little 
There is not rule to bent when it is technically not possible.
I’m building a typeface in which the stems are components, so that in interpolations, stems that have to be equal are equal. But than I would have to find a way of breaking the components on the generated fonts. I just realised that FDK’s “remove overlap” doesn’t break the components, so this is not a good idea.
Anyway,
When I generate the fonts Glyphs seems to break the components before interpolating, because sometimes the same component looks different depending where it is in space and surrounding outlines.
Couldn’t this be done in reverse? Say, first interpolate everything keeping components as components and decompose them after?
It is first interpolated and then decomposed. Can you send me the file to have a look?
File sent. Thanks!
Do the coordinates of the components get rounded to integers after interpolation and before they’re decomposed?