Richel, Ristolainen,and Scandella are unavailable.
Kane will cost a 1st, a B+ prospect and likely something else
Reinhart is available but in return it would have to be for a 24 or younger Dman. He is available because buffalo drafted Mittlestadt.
ROR could be traded as part of a pure hockey trade for NHL players. I don't see this happening this year.
Buffalo does not need young forwards. They have Eichel, reinhart, bailey, baptistery, fasching, and Rodrigues ending their waiver exemptions this season so they will be on the 23 Man next year. Nylande is on a sliding ELC. I didn't not expect him to get called up and burn his first year in part to strategize for a potential expansion draft in 2020. In the AHL they also have CJ Smith and a couple other forwards. They also have drafted Pu, Asplund, Davidsson, and Mittlestadt. That is at least 12 young forwards.
On defense buffalo is lacking in prospect depth. They have Guhle and Stephens starting their ELC this year. They have 5 others that were 3rd-5th round draft prospects playing in college or Europe.