Starting lineup will be Kyrie, Klay, Luka, PJ, Lively. That is a great offensive lineup and (at best) a passable defensive lineup. Ultimately I don't think it matters much though because substitutions will start happening within 5 minutes of the start of the game.
I'm thinking you will mostly see 2-man combinations of Luka / Klay, Luka / Kyrie, and Kyrie / Klay + 3 defenders on the court. Really the only other "offense only" player is Hardy who will get some burn, plus it is guaranteed there will be injuries during the season for him to step up. Otherwise you have a bunch of mostly defensive oriented players (Exum, Grimes, Naji, Maxi, OMax, PJ, Lively, Gafford) to mix and match around those offensive initiators.
As far as closing lineups, I think it will be driven by the score. If the Mavericks are behind you will probably see Luka, Kyrie, Klay lineups. If they are ahead someone will be subbed out for another defender (or two). I imagine that will be pretty fluid. To round out the roster I would like them to get DSJ if possible. Having a defender for smaller, quicker guards would be nice to have on the roster.