I do believe the CBA requires a minimum cap hold of the minimum rookie salary for every open roster spot. So if 13 are required and the Lakers only have Nash, Kobe, and Love on the roster, they would still have an additional cap hold of around $5 million. The minimum rookie salary for next year is $500k. Plus they have cap holds for the various exceptions (Mid-level and Bi-annual) but I am not sure that those apply if they are under the cap. There is also a cap hold for any trade exceptions.
Anyway, their 3 contracts, along with roster cap holds take them to around $56 million, which doesn't leave much for a FA. If the cap is $63 million, which is what is being reported, they have around $7 million to play with, if they manage to get Love. I assume there would be no cap hold for their first round pick because they would have to trade that to get Love.
Kobe--$25 million
Nash--$9.7 million
Love--$16.5 million
Cap holds--$5 million (without draft picks, or MLE)
I assume they are going to have to do something with that Nash contract.