I wanted to show you a list of all the character things Disneyland Paris has. As I think Disneyland Paris is very similar to DL as in audience and mentality, it might give a glimpse what the options are
As you can see, we have 4 different character offerings during the Halloween season. This is in addition to pop up parades and the fab five waiving you hello in the morning and goodbye in the evening from the train station.
- Magic shots.
I know maybe not new for the US, but it is in Paris

But they keep updating these. I have been in July and early September and they have renewed now for the third time some of the magic shots.
Halloween, Cheshire Cat, Old Hag, Evil Queen, Stitch, Captain Hook, and the Hyenas are all new now. Plus in the Studios Tower of Terror is new, I'm not sure about Remy's.
- Selfie spots
Here you stand 6ft away from the characters and can take a selfie with them in the background. This sounds worse than it is. You are still close enough to have interaction with them. Face characters are close enough to talk to and fur characters still understand sign language. They still notice if you have a sweater, a bag, a plushie or anything that resembles their movie.
- Selfie zone
Here we can meet several characters. Like in the Studios we have Elsa & Anna together, in the Park we have Mickey and 2 other characters in Halloween outfits. Can be Pluto & Goofy, or Minnie and Donald are in the mix. For Halloween they also have 2x four villains, one line up has Cruella, Gaston, Frollo & Jafar. You all take your picture with them one after the other.
- Surprise
These are little 'shows', Maleficent is on the balcony of the castle, a big entrance with smoke and all, Diablo is with her. And over the speakers she talks to the people below how she is the mistress of all Evil.
Disneyland Park The Studios
I am not that familiar with DL, as only one visit, but I can see this happening in DL as well. One of the things we use are the theaters. I can imagine that Mickey and the Magical Map can have a set up similar to ours to have a selfie zone. Same for the theater where they perform Frozen the musical or the Royal Theater. All you need is a backdrop and a character.
I can see Tiana on the balconies at New Orleans Square talking to people
One of the pop up 'parades' in the Studios we have are Mr. & Mrs. Incredible going by on 'segways', that can very easily work in DCA.
Mickey's regular meet & greet can maybe be used as a selfie zone (don't remember how much space there was inside)
DL's biggest problem is that it's relatively small, so congestion happens easily. But with the reduced guest capacity and that it doesn't take that long to take a selfie, it should be very possible. And it would differentiate DL from WDW. I can spot some little corners on the DL map that can be cornered off to make this possible.
What I am trying to say is, that if DL follow's DLP's example, characters are not going to be a worry

If you need more pictures of how it all looks, let me know and I'll upload some .