I have some proof regarding the inclusion of Marvel character, Elektra. Normally associated with the hero, Daredevil, she is a female assassin known for wielding dual Sai's (large daggers). This is important to note.
Disney like to keep a balance of male and female characters, and Marvel has included her in media before such as Marvel Ultimate Alliance. I myself would love her inclusion as she is my favorite Marvel character, period. Disney Infinity 2.0 includes the new interiors in Toy Box mode. Various Marvel themed items are included, like Captain America's old shield, to various Iron Man suits. I noticed in a screenshot, Elektra's dual Sai's are hanging above the various Iron Man suits. (as pictured below)
Interior items so far have been based off playable characters only. (Subject to change)
I'd love to hear what you think.
EDIT: Here is the image that the item is based off: