Kinda hard to strangle a Shinigami though 
Yea, I know you and Lupin are coming across more and more like stands in for L and Light. Hell, Inufan still seem more Matsuda-ish to me than her own character. If I had more time to come up with a story, I could have done more with those charactizations....by more time I mean like October. Same could be said about Groovy's, as a Rem , Gelus, or Sidoh like Shinigami wouldn't work...so he's more like Ryuk. I've been more focused on the Christmas note...Mrs. Spooky's, Mafia's, Bebop's, and Lover's characters as they revolve more around the C-Note ending up in a world with a D-Note.
You're not an exact copy of Light though. No matter what Light might be going through, he would always keep his demeanor out in public. I see Light helping a lady he knocked over instead of dismissing her like you did. Despite the fact that you are quick to anger, I'm going for more of a slow burn for your character. Who knows what was running through your mind when you bumped into Mrs. Spooky 
As far as the Christmas tree, Lupin, and L...I'm not sure L even would have noticed or cared. Watari probably did most of that stuff, and L probably didn't pay any attention. He was used to working alone on cases...where as Lupin seems to be trying to keep Inufan focused. While Inu's out finding Christmas trees, Lupin's noticing a drop in killing and the sudden burst in Christmas carols from the prisoners. This could be the break in the case he's been hoping for, and he wants Inufan to work with him...not decorating some tree.
Did you ever look at a picture of yourself and see a stranger in the background? Makes you wonder how many strangers have a picture of you.