If Emmanuelle had won in 2012..

Yup. Don't see any way she overtakes that 12 Years a Slave girl and that other white girl's name I forget from Room. Bria something.

no as in she wouldn't be oscar-less? having won for AH?    

I think Lawrence's BAFTA in 2013 was largely to make up for not awarding her the year prior, and HFPA loved her so much that of course they'd give her the win for American Hustle. I think, however, SAG would still have recognized Nyong'o over her, and that performance is so much awards catnip and American Hustle lost so much steam that season that even if she hadn't won in 2012, I think the end result would still have been the same in 2013. She probably also doesn't win for Joy, so it's very likely Lawrence would remain winless if her career trajectory were the same.

The question is, would her career trajectory post-Oscar be the same? Does she still have the burnout phase when she takes a step back from the industry (barring the occasional Mystique appearance)? Does she take more interesting roles to capitalize on that momentum?

No. It’s not like she would have been considered overdue enough at that age to change any votes from Lupita to her

Furthermore, if she doesn't win the Oscar in 2012, does BAFTA feel the need to reward her because they feel they missed the boat the prior year? Could be Nyong'o just scores there as well and American Hustle becomes even more of a non-factor.

Science oven says "Yes, Oscar-less"

Indeed. With it having no shot at taking Actor or Supporting Actor, Nyong'o was the film's best chance at an above-the-line award aside from Screenplay. And while we saw Spotlight walk away with only two Oscars only two years later, that was a far more fractured race and year than 2013. But seeing the way American Hustle wheezed to a stop before Oscar night, I can't imagine Lawrence losing the year before would've propelled her that much further than she actually got. It's feasible she could've won, and I think the margin was probably slimmer than we'd like to think . . . but I still think Lupita had the edge based off the role and the film alone, regardless of Lawrence's momentum.

If she'd lost for SLP, there'd be enough good will for her to easily (in my opinion) destroy her competition.

12 Years a Slave could've won BP without winning anything else (I don't think it had stiff competition at all - there wasn't a chance for it to lose), but it always had Adapted Screenplay to snatch as well (that was their main chance of another award).

And I don't feel there'd be that much backlash because I don't really remember that Nyong'o was considered undeniable or all-time great or something.

So basically I disagree with you on every point 

I think people are applying the optics/politics of today to 2013/14. This was pre-Trump, pre-MeToo, pre-OscarsSoWhite. it was a different world in the entertainment industry.

And yet Lawrence still won the Globe, BAFTA, and multiple critics' awards. 

Who said that she did?   

What I've said is that this was likely one of the closest Acting races of last decade.

Lawrence was the favourite for best supporting actress, so clearly she could win the next year.
Lupita won, because it was just too soon to give a seccond oscar to Lawrence.-

Lupita Nyongo is a Kenyan actress, not an american one, in fact she was born in Mexico. So she made a lot of press with the latino community speaking in an almost perfect spanish.-


She still doing talking spanish to the latin media.-
Without Lawrence win the previous year and the push of Brad Pitt and the Hispanic Community she would lost.-
For win an Oscar you have being soooo famous and beloved by the Academy, being pushed by very influential people, or have a big support from your oscar voters community.-

She was pushed  by the Clooney-Pitt Gang, Fox Seachlights, part of the Africanamerican community and the latino community, without this support she would never won.-