1.) I'm a bit of an oddball in this regard, in that I draw my lineart traditionally on 11x17 paper and then scan it into the computer. I believe at 300 dpi. Then the pages get most of the white space around the edge cropped off. I think the size is typically around 2200 - 2500 pixels when all is said and done. Then I do all of the coloring and text at that size, and reduce it down to 800px to post to webtoons (and 940 for tapas).
2.) ah this got clumped into the above answer, but I guess technically 300.
3.) Before.
4.) I typically use 16 point font at the original scale, which reduces into something mostly readable at the output size.
5.) Hmm, I just make sure to select "highest quality" or wev when saving the final file out of photoshop. They still seem to look okay on webtoons.
6.) here it be: