Merge iPhoto/Aperture Library, Apple Photos into a Lightroom Photoshop 2019

Dear community, sofar I have been using iPhoto/Aperture and the last past year Apple Photo which means that I have 2 libraries that I now want to merge into one Lightroom (not classic). I am quite a newbie to LR and I am looking into a way to manage my 100K+ Photos in a more sustainable way.

1) Is it feasable without too much effort and if yes how ?

2) Can I use LR on iPhone/iPads without having everything double with Apple Photos on those devices ?

Thx