I fully expect a bumpy season, or at least until November/December. But I don't think losing Kane is as big of a deal as many would guess. Yes, making up for thirty goals is a massive task and last season Spurs would get into relegation fight without Kane, but there's new coach now, probably strengthened defense and attack seems to still be decent. I'd argue when Spurs lost Bale, they were more of a one man team than now and they survived it fine.

TLDR: I think 6th could be both achievable and considered a success in Ange's first season.