It depends. If they don't violate copyright laws and are not for commercial purposes, they might be okay. But if they copy official content without permission, it's likely illegal.
There aren't any. The Pokemon world is focused on adventure and friendship, not such inappropriate content. Such comics would go against the nature and values of the Pokemon brand.
First, you need to have a clear story idea. Decide on the characters, their adventures, and the overall plot. Then, start sketching out rough designs for your Pokemon characters and the scenes.
No. The Pokemon fan community generally values the family - friendly and positive nature of the franchise. Sexual fanfiction goes against these values and is not acceptable. It can make many fans uncomfortable and can also damage the reputation of the overall community.
No. The Pokemon fan community is generally about positive things like collecting, trading, and enjoying the battles and the storylines. Suicide is a very heavy and negative topic that doesn't fit in with the light - hearted and family - friendly nature of the Pokemon world. It's not acceptable at all.