He is entirely consistent. He believes the polls are rigged and that when he has a lead it is a real lead. Grin all you like - there's no inconsistency.
No. His supporters believe this (or at least the stupid ones do) but I do not believe that Trump and his campaign team expect to win.
Firstly, they have taken resources away from the transition team planning (ie preparing appointees for the first days of government) and reallocated them to campaigning.
Secondly, Trump does not reject all polls. He appears to accept polls which show him in the lead, including polls which are known to have flawed methodology (like the LA Times one, which can move 3-4 points depending on whether a single black Trump supporter is included in the panel or not).
All polls are wrong, but the likelihood of all the polls being wrong in the same direction is so small as to be negligible. It's still not impossible for Trump to win, because there are undecided and third party voters whose votes may be in play, but it's looking rather far-fetched at this point and all the evidence is that the Trump campaign team know this.
That's what the "rigging" narrative is about - it's a sore loser getting his excuses in early.