If you want to discuss/grade Spurs in the league then it makes little sense to drag in results from the League Cup and Europa League.
I agree that Spurs have had a relatively easy fixture list so far, but you've exaggerated things because it's not just last season's top 6 to consider in comparing fixture difficulty, it's also this season's top 6 so far: for example, the away draw we got against Leicester now seems like a decent point.
I flatly disagree that "compared to last season" is a totally meaningless stat, although (like for all football stats) its validity increases as the season wears on. You've singled out the Villa and Sunderland results as accounting for "5 of the 6 points", but this selection is arbitrary ... you might just as well say that our beating City this time and drawing with Liverpool accounted for 4 of the 6 points. And I'd also say that a comparative +14 GD also has some meaning as a pointer towards Spurs having improved compared to last season.
As for the remaining games (and their comparison with last season), whilst it's valid for you to point to the good results from last season (e.g. beating Arsenal at home), you've ignored the bad results that wouldn't be expected (e.g. losing at home to Newcastle, Stoke and WBA). So even if lose at home to Arsenal (say), we'll still be on course for 70 points if that is balanced out by winning this time at home to Newcastle. So yes, I stand by my view that, since we've done a fair bit better comparatively so far, it's not too difficult to imagine that overall we'll do at least as well as last season from here onwards.
From what I've seen so far, I'd say that City and Arsenal are almost certainly going to finish in the top 2, with the other 2 places being a contest between Man. Utd, Spurs and Liverpool. (Chelsea are gone and won't come back this season). If you're a United fan then I'd say you're being too complacent if you think Spurs thus far are only on course for 5th or 6th, because thus far I'd say we're a definite contender for top 4.