The number 18 bus also goes from Wembley Central to Euston, although it'll take an hour at that time and waiting for one is pretty awful as the traffic stops when the stadium empties. On the plus side, it is far less crowded.
The overground train from Wembley Central runs every 20 minutes on...
The Wembley are is all residents parking on days when the stadium is in use. Your best bet is to park at a tube station in a different area. Stanmore is at the end of the Jubilee line and the tube is 10 minutes direct to Wembley Park. Last time I went, there was a massive car park there.
For...
I've done it a few times for Legends Days over the last few years and have yet to see a replica shirt in there. They specifically say on those tickets "no replica shirts", but that could just be a LD thing.
I live about 4 miles away from Wembley and the only time I'll go is if they do the local residents discount. I'm not paying £65 for a ticket when I can pay £20.