I'll be very surprised if Irene isn't in it. I expected her as DLC also, but then again I didn't realize TN would do this
Believe me, that tweet about more characters after Phase-4 IMO wasn't really wrong until they decided to release/change enough content for a third remake. The same for that new stageS in DoA5UA (still hoping for another stage for DoA5U, but at this point would be counterproductive for TK cut a possible exclusive from DoA5LR...).
If DoA5LR is going to expand the story mode (as the temporary cover with Kasumi and Phase-4 could hint), then all the new in disc charas of 5LR will be very likely part of it. In a such case could be more likely to expect in disc, rather than as eventual later DLC, new characters higly related to the plot as Irene or Donovan.
Hmmm guys don't expect Tengu to come back. Sorry to say that, I don't mean to be rude, but he was/is/will be nowhere as popular or deep as Nyotengu. TN's idea to bring Tengu-dou back to life via Nyo was the best thing to do in terms of marketing, gameplay and storyline.
A Bankotsubo skin/costume on the other hand...
I agree: while, even if unlikely, charas as Raidou, Genra or Shiden have still a chance to be part of the roster, Bankotsubo, Kasumi Alpha and Spartan 457/Nicole (putting aside her copyright matter) are definitely out now that the game have charas working as replacements for them.
But maybe in a future game, realized on the TTT model with a dream roster rven contemplating clones slighty different in the movesets, we will see again these characters together with their new alter egos...
@KwonJigglypuff : from the words of Emperor Cow after his last travel in Japan, Hayashi said him that Ryo is too much similar to Akira (implied for adding him in a game already including Akira).