I'm not sure we understand each other. I don't care how complex the sub-assembly is (the shock). As long as the sub-assembly have the 2 LCSs available to the bigger assembly, it doesn't matter if the subassembly looks like a sock observer, a piston, a shaft or whatever... there is a body with 2 atta...

Can I attach a subassembly/part by more than one attachment point? You can, if you have multiple LCSs in the subassembly. For the sake of the example, lets say you attach a shaft attached to the 2 parts. If the shaft have LCSs on both sides, so attach part A to LCS_1 and part B to LCS_2. If you wan...

Just a personal preference, but if it is not available, then I will use multiple files. I hate the fragility of multi-file designs in general, not a FreeCAD specific issue, but sharing directories between windows and linux have played bad for me in the past. The solution is simple: Don't use window...

I'm not aware of such option.
Why do you want one file?

Sub-assembly in a separate file is exactly what you want.
Especially if you have many instances of the same sub-assembly.

If I had to do that design, I'd leave the animation master sketch and LCS in the top level assembly, and model all the sub-assemblies (rotor, tail-rotor, piston ...) as separate entities, but such that each sub-assembly is static. Then, I'd import all sub-assemblies into the top-level assembly and ...

Go go "Tools -> Project Utility"
That's the way to ZIP the changed files into the FTStd again

You describe the classical use case of a wizard. Qt offers the class QWizard for this. There you can also define for a page whether it allows you to go back. So, the easiest when embedding a QWizard into a Task dialog is to override the method getStandardButtons() to return QDialogButtonBox::NoButt...

It really depends on what your command does; if you have optional values, maybe these should have suitable default values, but if you really need the input from the user, then yes, a sequential display of task panels, like Draft Text does, may be best. This command doesn't handle going back and for...

I've tried to add few dialogs to task view, but it looks I'm doing something wrong... I've expected that calling Gui.Control.showDialog() with different dialog classes will do the trick, but it looks like it does not. I get "Active task dialog found" for the second call of showDialog. I found that s...