So if Arcee/Chromia is wave 5, and Tankor/Rattrap/Crosscut are wave 3, that should mean Nightbeat/Jhiaxus/Windblade are definitely wave 4.... which would be three waves released by April. (during a time when Retailers are less likely to stock new Transformers due to the Movie toys coming in May)
Probably best to pre-order these early, in case BBTS gets limited stock again.