Did Johnson & Stein cost Clinton the election?

In light of the recent and almost completely unexpected presidential election results, I've decided to see whether third party candidates were responsible for this outcome by stealing votes from Clinton.
First, I will list the margin of victory for Trump (in %) in key swing states, according to CNN (i.e. %Trump-%Clinton):
Florida= 1.3
Pennsylvania= 1.2
Ohio= 8.6
Michigan =0.3 (weird stuff is going on here, with an appeals court recently rejecting an already-underway recount initiated at Jill Stein's behest.)
Wisconsin=1
Georgia=4.7
North Carolina=3.8

Now let's compare that with the % of people who voted for Johnson (J) and Stein (S) in each of these states (in GA and NC, Stein was not on the ballot):
FL: J=2.2, S=0.7 J+S=2.9
PA: J=2.4, S=0.8 J+S=3.2
OH: J=3.2, S=0.8 J+S=4
MI: J=3.6, S=1.1 J+S=4.7
WI: J=3.6, S=1.1 J+S=4.7
GA: J=3.1
NC: J=2.8

Suppose we then divide the margin of victory in each state by the % of voters who voted for J+S combined. (Bear in mind that if the number we get is >1, there's no way third party voters could have cost Clinton the election in that state.) Then this is what we get (results rounded to 2 decimal places):
FL: .45
PA: .38
OH: 2.2
MI: 0.06
WI: 0.21
GA: 1.52
NC: 1.36

Now we can rule out OH, GA, and NC because there's clearly no way Johnson and Stein could have cost Clinton those states. So what about the four remaining states--FL, PA, MI, and WI? Well, if Clinton had won all of them, she would have gotten 75 more electoral votes than she actually did, for a total of 307, which is not only enough to win, but also even more than Trump actually got (albeit by only one).

Exit polling data give us a good idea of how third-party voters would have voted if the race was only between Clinton and Trump. According to CBS, 25% of Johnson voters said they would have voted for Clinton otherwise (C), 15% said Trump (T), and 55% said they would otherwise not have voted (O). Similarly, about 25% of Stein voters said C, 14% said T, and 61% O. So let's multiply the % of each third-party candidates' voters in each of these 4 states.

FL: J: 2.2*.25=.55% more votes for Clinton, 2.2*.15=.33% more for Trump
S: .7*.25=.18% more for Clinton, .7*.14=.1% more for Trump
FL total: .73% more for C, .43% more for Trump
So C would have been .3% closer to winning FL without J and S. But this is not enough, because she would still have been 1% behind Trump there.
PA: J: 2.4*.25=.6% more for C, 2.5*.15=.38% more for Trump
S: 0.8*.25=.2% more for C, 0.8*.14=.11% more for Trump
PA total: .8% more for C, .49% more for Trump
Again, in PA, C would have been about .3% closer to winning without J and S. But this is still not close enough, as she lost the state by 1.2%.
MI: J: 3.6*.25=.9% more for C, 3.6*.15=.54% more for T
S: 1.1*.25=.28% more for C, 1.1*.14=.15% more for T
MI total: 1.18% more for C, .69% more for T
Without J and S, C would have been .49% closer to winning MI than she actually was. Because she lost the state by only .03%, she would have won MI without J and S.
WI (all the same as in MI, weirdly enough): J: 3.6*.25=.9% more for C, 3.6*.15=.54% more for T
S: 1.1*.25=.28% more for C, 1.1*.14-/15% more for T
WI total: 1.18% more for C, .69% more for T
Without J and S, C would have been .49% closer to winning WI than she actually was. But this would not have been enough, because she lost the state by 1%.

So it looks like Clinton would only have won the ridiculously close Michigan race without Johnson and Stein. So she'd have gotten 248 electoral votes, compared to Trump's 290. But Trump would still have won because you only need 270 electoral votes to win.

So the answer to the question "Did Johnson & Stein cost Clinton the election?" seems to be "No."

I should note that Vox looked at this same subject already and concluded that the answer to the title of this post is no. The Washington Post, in contrast, concluded that without Johnson & Stein, "Clinton might have won, based upon these data, but only by winning both Pennsylvania and Wisconsin. If Trump held onto even one, he would have kept an electoral college majority." The WaPo also noted that in this hypothetical 2-candidate scenario, "In Pennsylvania and Wisconsin, Clinton and Trump would have tied at 48 percent apiece."