Courtney Lee could contribute on both ends, but he's far from essential. OJ Mayo is great on offense, but he needs to learn/commit to defense to be an essential player for a title team.
I'd love to have either, especially OJ, but I wouldn't give up yet on JJJ. If S&T Dooling + SW + Moore can work, ok. If not, get Pietrus as a wing defender and we're set.
Our key players are Rondo, Bradley, JET, Pierce, Green, Bass, Sullinger and KG. Wilcox and Pietrus will contribute, and hopefully we can get something out of the young kids other than Sully. You could add OJ or Lee to the key players, but the essential players are Rondo/Bradley+JET/Pierce/Green/KG.