Mild chocolate is the one you find in most normal chocolates. It's sweet. White chocolate is white in colour (duh), and it's made out of cocoa butter, and doesn't actually have a chocolatey flavour.
To a degree. 90-95% dark is great, but once you go to 99% dark, the only taste left is bitter.
It's actually not that hard. There are 2 timelines.
The old timeline has 2 sets of time travellers. The first is Elria and her dad, they travel back to the point in time where Reid is still alive. There, Elria is born again without any memories. The second set of time travellers are the leftover...
It's one of the ones provided by Mangadex. Just type 'finnawoke' in between two colons :)). Or, click on the smilies tab at the top of the chatbox and scroll till you find the ones added by Mangadex.
Pretty sure the MC is still a kid. He just has memories of a past life. So, it's like a kid with access to the video of someone else's life. He hasn't experienced the other life, just has access to the memories of it.