The demo colors are incomplete as is. All the alts have not been confirmed whatsoever.
Ms. Pac-Man shares IP rights with someone other than Bandai-Namco. She's unlikely to be a costume or playable as an echo due to this. She also works 100% fine as a costume either way.
As for Ashley, she's vastly the most popular of the WW characters besides Wario himself. If anyone gets playable among it, it's her.
Mrs. Pac Man is definitely a problem IP wise. Simply put, the issue is (and I think I saw someone else mention this while I was browsing this thread) that Namco didn't create the character, their North American distributors Bally Midway did, and they took the core game from a student project called "Crazy Otto" which they purchased. A major problem that arose over time that eventually resulted in a court case that effectively toppled Bally Midway was that they were repeatedly coming up with unauthorized sequels. In hindsight it's easy to see why: Namco's Pac-Man sequels were each incredibly different from each other, like Super Pac-Man and Pac & Pal, with very different mechanics that moved away from the "formula" the first game created. It is very important to note that Namco begrudgingly made Mrs. Pac-Man an "official" entry in the series due to its overwhelming popularity, but they still were trying to do very different things in their sequels at this same time. In NA, this was not well received so Bally Midway created more samey sequels/upgrade kits like Pac-Man Plus, Jr. Pac-Man and even an arcade/pinball hybrid called/starring Baby Pac-Man (oh yes, and Professor Pac-Man). However these actions were never sanctioned by Namco, and they were (for better or for worse) successful at revoking the license.
That said Namco has had a very inconsistent history with the characters Bally Midway created. Indeed, Mrs. Pac-Man, Jr. Pac-Man, Baby Pac-Man and even Professor Pac-Man have appeared in licensed titles over the years. This was especially prevalent in the late 1990's-early 2000's with the Infograms licensed PC games and Namco's own Pac-Man World series. However, the original Bally Midway arcade games have very rarely been reissued by Namco. Mrs. Pac-Man is a lone exception due to its popularity and "official" status, but even then it is often an unlockable (or these days, separately paid for) in official Namco arcade collections.
What this means is that Mrs. Pac-Man is not an impossibility, especially if Namco were pushed hard enough, but it's not exactly a period of their history they look fondly on (a licensee beating them in NA and culminating in a lawsuit), and the nature of the character's creation means that there may be additional license stipulations that make her inclusion in Smash difficult to achieve.