Advice for 8D7N in Shenyang > Jilin > Harbin

I'm planning a trip (for about 4-6 ppl including myself) in January, mainly for Harbin's Ice Festival and thinking of stopping by other northern spots as well.

The duration itself is 8D7N and I'm planning it like this:

Day 1 - Flying into Shenyang (AM)
Day 2 - Shenyang
Day 3 - Shenyang > Train to Jilin
Day 4 - Jiilin
Day 5 - Jilin > Train to Harbin
Day 6 - Harbin
Day 7 - Harbin
Day 8 - Flying back from Harbin (PM)

My question is whether one full day is sufficient for Shenyang / Jilin respectively? Or should I just pick either one. Train times are flexible for now so it could even be a day and a half for each place?

In Shenyang, I plan to visit the imperial palace, mausoleum, Hunhe river, food markets - I think that should be doable in a day or two? In Jilin, I'd like to visit Rime Island but I read that it's quite a drive out so probably just that for the day.