1.) Murdoc was 35 while 2D was 23.
2.) Not really sure about it. I bet it was a dark violet color when she was young
3.) It's not confirmed, but more likely the Boogeyman is after Murdoc's soul even though Murdoc sold his soul to Satan when he was young
4.) This is also not confirmed but it could be Murdoc himself, the boogeyman, or even Murdoc's brother, Hannibal Niccals
5.) 2D moves to a specific location in a city as seen in the plastic beach ident.
I hope this helped, and good luck with the fanfic!