Toon boom exporting setting problem (from 8bit color depth to 32bit RGBA & transparency problem&size reducing problem)

Hello, I’m trying to export my animation project to image sequence and import to after effect. And I’ve faced three problems while doing it.

I disabled the drawing mode layer, checked on the ‘colour with transparency’ on the image exporting window, and set the file as PNG( I tried TGA as well), but,
the image sequence still has the black background when I bring them into After Effect. So I eventually had to export my image files into PSD, then it worked.
Is there a reason that I’m not able see my files with transparent background with TGA or PNG?

There’s only a 8bit option on the color depth tab of the image exporting window. For the film I’m trying to make, I need to export image files into
32bit RGBA setting. What can I do to change the color depth setting?

I surely set my scene setting as 1920 x 1080, but once I bring in the exported image files into an after effect project, the images are always smaller than
1920 x 1080 ratio.

I even tried to customized the ratio to 1920 x 1080 on open GL frames window when I export to make sure the size won’t get smaller.

Is there a way to solve this size problem?