This is my best guess as to what the opening roster will look like... taking into account the cap space considerations, waiver exempt status of players as well as cap hits of players.
Kane-McDavid-Brown
RHN-Drai-Hyman
Janmark-McLeod ($2.1 million)-Foegele
Pederson-Ryan-Lavoie
Forwards $45,924,125
Nurse-Ceci
Ekholm-Bouchard ($3.5 million)
Kulak-Desharnais
Niemelainen
Dmen $26,275,000
Campbell
Skinner
Goalies $7,600,000
Dead cap and bonus carryover $2,766,667
Total cap: $82,565,792
Cap limit: $83,500,000
Under cap limit by $934,208
They start with a 21 man roster.
This gives the team the option of accruing cap until the deadline OR calling up either Broberg ($866,333) or Holloway ($925,000) at any time (as they are waivers exempt) and there is enough space to accommodate one of them on the roster to run a 22 man squad.
Of course they could start with both Broberg and Holloway on the roster instead of Pederson and Niemelainen BUT that would mean they would have a 21 man roster with only $680,375 in cap space... not enough to run a 22 man roster.