Kings are gonna get wrecked if Richards contract is reinstated. They'll be $4m over the cap.
Anyways regardless of what happens with Richards' contract this year, Kings have either $11m or $16m(depending on Richards) to work with assuming the cap doesn't go up. The lion's share of that will go to Kopitar. If they get lucky, they get him for $8m. If not he'll be worth about $10m.
Assuming the Kings do sign Kopitar, they'll have somewhere between $1m and $8m to work with. They'll need at least one forward, one defenseman, and one goalie. Probably a top 6 forward since they're probably lose Lucic, one bottom pairing defenseman, and a backup goalie. They don't really have a whole lot of space in general but they could probably be fine if they win the Richards thing. If they lose, they're pretty ****ed because keeping his contract or buying him out will hurt them a lot.