I doubt Robertson makes it out of camp at this rate tbh, mainly just because of the waiver eligible competition he faces - he'll need to be excellent.
I like that Järnkrok quickly showed off his shooting talent and probably provided some comfort for fans as a possible Top 6 option. Looking at his statistical profile in recent seasons, I don't see why he couldn't possibly experience a jump in production to close to 50 PTS in our Top 6. He's paced at around 40 in recent years as is - also adds some defensive value.
Three lines I see eventually settling are:
Bunting-Matthews-Marner
Nylander-Tavares-Järnkrok
Engvall-Kämpf-Aston-Reese (matchups)
That leaves a line formed around Kerfoot and Aubé-Kubel as the last one, and I'd imagine that last spot goes to the best of Robertson and likely the top waiver eligible guys in Malgin/Gaudette/Anderson/Simmonds.
TOR already had Robertson-Kerfoot-Aubé-Kubel together, so I'd think this overall framework is at least a thought.