i would need more info as to what Spooner and Khokhlachev bring to the table.
Spooner has high end #2C and PP ace potential. Spooner has high end wheels, but is relatively soft. Not to the same degree, but has some of those Skinner-like skates at 10 and 2 moves. Has a good shot, but is always thinking pass first. A lot of his AHL moves may not translate to the NHL level and its unclear how he will adjust.
Koko isn't a straight shooter or passer. More quick than fast. More undersized, but has more jam in his game than Spooner. Also good #2C potential, but probably a lower ceiling for straight points than Spooner. Has probably passed Spooner on the depth chart, but you could argue that is more because of playing style fit in the Bruins system than potential and play.
It assumed a lot on these boards that the Bruins only have room for one of these guys.