From experience, I'll tackle your queries:
Yes you can import a sketch easily. I done it many times (all my entries for the Spider-Man jam were done this way).
Yes. Most tools have a 'correction' setting that you can tweak by giving it a numerical value.
2) Auto-correct wobbly lines while inking (this is a big one)
Here is what I use most of the time:
Again yes. You can export to Photoshop easily and keep the layer information intact. Note the program states up to five layers, but I've been able to do ten with no problem. However, if your artwork goes out of the predefined work area (the blue box) make sure you check the option for full page export. Discovered that the hard way on my villain jam entry of Malificent.
3) Export finished ink work into other programs for coloring (ex. Photoshop)
Hope that helps.
"The Enrichment Center is required to remind you that you will be baked, and then there will be cake." - GLaDOS