Force automatical alignment while ignoring other paths and components

Is there any way to force a select component to be automatically aligned (width/sidebearings are locked to the original base glyph) and to ignore anything else that is added whether it is paths and/or components (with automatic alignment disabled)?

I have a scenario where a base glyph is being repeated as a component in a number of other glyphs to which paths are added to extend a stem, other paths are added as an underline, and mask components (auto-disabled) are added to create gaps.

I realize it isn’t typically a good idea to mix components and outlines but in this case, the immediate goal would be to keep everything in sync while the font is in progress by using the base glyphs to draw the main outline and set the spacing…eventually, everything will be decomposed.

That is not possible. It could result in moving the unaligned stuff relative to the aligned component. You would need to put that extra part in an none exporting glyphs and use components and anchors to add it.