I don't know too much but I'm sure there's someone here who can correct me. I can tell you what I like about each. Each of these check the boxes on what this team needs.
Sandin Pellikka
He's excellent at transitional play and moving the puck.
Danielson
He has great hockey IQ, quick and can carry the play
Leonard
He's a power forward, plays with intensity and drives net hard which could be good on power plays.