You mentioned that you'd like to say that she is a cat and that's just how it goes. Well, I have some bad news for you. She is an F1 (very distinct and important difference) and yes, that may be JUST how it goes.
Much of the time people take in earlier generations with high expectations and they end up being disappointed with the results. You have a wild animal and your only expectations initially should have been to simply become a non threatening part of her environment. It is important that you understand this, and that you also understand that sometimes these animals only bond to certain individuals in their new home or none at all. She may never bond to you in a way that you prefer.
I know you mentioned that you previously considered rehoming, but to tell you the truth this may not have even solved the issue with her even if you did. In general, F1s are NOT fond of change at all. They do not thrive in the midst of it and it can be detrimental to their socialization and development to be tossed into big changes.
A number of things could have lead her to be this way. It could even be that she was just not socialized well enough at her first home. We did such a hefty amount of research before taking our F1 boy home but I gotta tell you I heard so many horror stories regarding F1s not meeting their owners "pet" expectations.
All you can really do is continue the way that you are and hope things change over time (and this may be a lengthy amount of time), but unfortunately, when these EGs choose to bond they usually do it right off the bat and sometimes things will never change after that point. Our Dexter can be lovey dovey sometimes while at other times, yes, it does seem like he has bonded to our SBT Bengal and is just "tolerating" us and our presence. Sometimes it's very different and he is all love and cuddles, but regardless he will never sit in our laps contently or snuggle with us; he will only do this with Bauer.
You are doing the right things in rewarding her with treats and this will (hopefully) associate your presence with good things. You could also try using one of your t shirts that smells like you (and i do mean a standard t shirt because this will not be pretty) as a food mat under her bowls so that she can smell you while she's eating and that might also help with that association.
Also, Our boys love freeze dried chicken treats. Boil some plain unseasoned chicken breast for 45 minutes. Lay it out on a cooling rack and when it's cool shred it into bite sized pieces. Put the pieces back on the cooling rack, stick the whole thing in the freezer, and let it dry out in your freezer for about 7 days. You can then toss the dried out pieces into a large freezer bag and store them in the freezer. If they feel moist or are greasy at all to the touch, leave them in longer. Also, try doing some clicker training with her. This positive reinforcement is great for bonding and the cats really do have a lot of fun with it. Try including your partner if she becomes difficult with you and see if she will take to both of you. You can get a clicker for cheap on amazon or at petsmart. If you google clicker training videos you will get some really great in depth information.
It looks like it might be a rough road for you, but that is sometimes (often really) how it is from what I gather. Female cats in general can tend to have a "tude" and I have heard plenty of times that this can mainly be directed at other female cats and humans alike. EGs in particular, are a tremendous amount of work and things do not always pan out the way you hope because at the end of the day they are still wild animals - not domestic. Every cat is different and has a different unique personality - let alone the EGs.
I hope that you guys can find some middle ground and that things improve. This could be a very SLOW and even grueling process but if she does come around I can promise you (though i'm sure you already have an inkling) that it will be well worth it.
Do post pics as well
EDIT***** Missed her age as well when I first read your post. Most early gens are rehomed at around 8-9 weeks specifically so that they can form a bond with their new owners early on. Not sure why yours was rehomed so late. That sounds to me like plenty of time to either A) form a permanent bond with the previous owner or B) form a permanent dislike toward females that she may have already had. I would say bring around a female friend of yours and see if she acts the same way, but I don't think that overcrowding her with new people is necessarily the best idea either.