Rasmus Dahlin (1st overall 2018) got 3 years @ 6 mil.
Nolan Patrick (2nd overall 2017) got 1 year @ $874,125, followed by 2 years @ 1.2 mil.
Patrick Laine (2nd overall 2016) got 2 years @ 6.75 mil, followed by 1 year @ 7.5 mil.
Sam Reinhart (2nd overall 2014) got 2 years @ 3.65 mil, followed by 1 year @ 5.2 mil.
Nail Yakupov (1st overall 2012) got 2 years @ 2.5 mil, followed by 1 year @ 875k.
Ryan Murray (2nd overall 2012) got 2 years @ 2.825 mil, followed by 1 year @ 2.825 mil.
Erik Johnson (1st overall 2006) got 2 years @ 2.6 mil.
Dahlin and Laine both got higher cap hits, but Dahlin was the only one who got more than 2 years on his 2nd contract, and all of them were/will still be RFAs when those contracts end.
Kakko has 54 points in 151 career games. Reinhart didn't make it to the NHL full time until his D+2 season, but he had 140 points in 252 games when he got his 2nd contract. Yakupov had 88 points in 192 games.
I'm expecting Kakko to get a 2 year deal, maybe 3 years, between 2 and 3 mil per year.