When Chelsea are offering him the largest and longest contract that neither United or Bayern will match, it could be a point of deliberation, I’d think. At that point Kane has a decision to make between potential trophies and more money in a contract than he’ll ever get a chance of again - plus the belief Chelsea can be resurgent. It’s also his last elite earning one, so I could understand him opting for it.I don't think Kane would pick either of them over United (especially as Chelsea won't be in CL) and Levy wouldn't sell to a local rival I don't think. United have the global rep for it to actually be worth it for Kane too, and we are much closer to actually competing for the title than Newcastle is. Kane grew up with United being the biggest club around, so the reputation of the club will have some impact for him.
It'll come down to Bayern or United IMO. At United, Kane would become all time PL top scorer and be the step up to compete for the title. At Bayern, he would guarantee league titles every year but in a league he doesn't care about, but then compete for the CL. More I think about it, the more I think we are by far the best positioned to get him.
Of course, us being sold to an obscenely wealthy state etc. does probably negate the financial gulf there’d currently be between our proposal and what both Newcastle and Chelsea could offer.