Sure, the Noragami manga is completed. It was a great ride with an ending that wrapped up the plot nicely. If you haven't read it yet, it's worth giving a go.
First, get the right costume. Look for a bright yellow Pikachu onesie or make one yourself with yellow fabric and black accents for the ears, tail, and markings. Then, focus on the face. You can use yellow face paint to complete the look. Don't forget about Pikachu's rosy cheeks, which can be added with a bit of pink blush. Also, practice Pikachu's cute poses and expressions, like its shocked face or its happy hopping pose. This will make your cosplay more engaging and fun.
If the cosplayer traveled through the anime novels that they cosplayed, they might find some unexpected plots. For example, they might encounter their own characters and communicate with them. Or they might discover that something different was happening to their characters than they knew. In short, this kind of plot might surprise and excite them.
Noragami is about a minor god named Yato. He wants to have a grand shrine and a lot of followers. He meets a girl named Hiyori who can partly leave her body due to an accident. They get involved in various supernatural events and battles against other spirits and gods. Yato also has a regalia named Yukine who he has to deal with as Yukine has his own growth and problems.