1. To know how to move images from Aperture library to Lightroom, please check the below article.
2. You can import either all of the images or just the one you want to work on as Lightroom does not work on the real images, it is going to work on the previews linked to the original image.
Yes, you can arrange images inside Lightroom which will reflect outside as well.
3. No, while im[orting images into Lightroom you will get the option either to copy, move or add images to Lightroom.
Copy As DNG-Copies photos to the folder you choose and converts any camera raw files to the Digital Negative (DNG) format.
Copy- Copies the photo files to the folder you choose, including any sidecar files.
Move- Moves the photo files to the folder you choose, including any sidecar files. Files are removed from their current location.
Add- Keeps the photo files in their current location.
4.The Format would be same as of the image.
5.You can import images from your SD card as well.
Thank you, sarsaxen. I will read the links you provided.
I have another question. How do I delete a Lightroom library photo that was uploaded from my Android? Are all library images private by default until I make them public?
Yes, you can simply right-click on an image and can remove it from Lightroom.
Yes, all images are private by default, only you have the access to them until you make it public and share with anybody.