I think a third possibility is Engvall. Moving his cap hit would allow the Leafs to bring back Liljegren and keep an extra player up.
Trading Holl would give us enough room for Liljegren but it wouldn’t give us enough room for a 21 man roster.
Holl is probably the last resort. He has the lowest cap hit and the Leafs lack defensive depth (especially guys who are RD and play like he does) with a lineup that has had a history of injuries on the back end. Even if he may be healthy scratched at times with a fully healthy lineup, I doubt we will have a fully healthy lineup for too many games anyways... And he allows us to rest Muzzin and Gio during the year.
Kerfoot, when all is settled, is likely a 12/13 min ES + 2 min PK guy while Engvall will probably be a 12/13 min ES+ 1 min PK guy with one of them getting some PP minutes too (right now it is Kerfoot).
Current:
ES Lines
Bunting - Matthews - Marner
Malgin - Tavares - Nylander
Engvall - Kerfoot - Jarnkrok
ZAR - Kampf - NAK
PK Forwards
Kampf - Marner (2 mins per game)
Kerfoot - Jarnkrok (1.5 mins per game)
Engvall - ZAR (1 min per game)
NAK (only plays if one of the above guys is in the box)
2PP Line
Bunting
Jarnkrok - Kerfoot/Engvall - Malgin
Giordano/Sandin
If you trade Engvall:
ES Lines
Bunting - Matthews - Marner
Malgin - Tavares - Nylander
Robertson - Kerfoot - Jarnkrok
ZAR - Kampf - NAK
PK Forwards
Kampf - Marner
Kerfoot - Jarnkrok
Robertson - ZAR
NAK
2PP Line
Bunting
Jarnkrok - Robertson - Malgin
Giordano/Sandin
If you trade Kerfoot:
ES Lines
Bunting - Matthews - Marner
Malgin - Tavares - Nylander
Robertson - Engvall - Jarnkrok (they may still split draws like Kerfoot and Jarnkrok currently do).
ZAR - Kampf - NAK
PK Forwards
Kampf - Marner
Jarnkrok - ZAR
Engvall - Robertson
NAK
2PP Line
Bunting
Jarnkrok - Robertson - Malgin
Giordano/Sandin
I think either scenario is more than fine for the Leafs. Robertson gets to drive the 3rd line if the Leafs think he is ready for it.