What will I lose migrating from Aperture 3.6 to Photos 3 ?

Hello all,

I resisted for years but I think the time has come to migrate from good ol' Aperture 3.6 to the latest and greatest Photos 3 (in macOS High Sierra).

I know both apps are not for the same uses or users.

However I'd like to know if I will somehow lose the following Aperture features (those that matter most to me) in the migration process:

• stacks (I use them a lot in Aperture)
• edits made to my originals (masters) in Aperture: will I get both original and edited images in Photos 3?
• geotagging: over the years I imported into Aperture a lot of GPS tracks from an iOS application, in order to geotag my photos (I do not have a GPS-capable camera). Will I lose all that GPS data?
• comments or captions that I added to the "Description" field of some photos

By the way: I also have old iPhoto libraries lying around. What is the best way to import them into Photos 3 too? Should I import then into Aperture before, and then migrate everything to Photos 3 in one move?

Thanks for any help!