yes.
a. if we are to believe the redditleaker, then since the beginning of march, o'brien is spiderman and his questions in regards to the character are just the same as paul rudd and benedict cumberbatch. so, that's that and we just wait and anticipate the official announcement.
b. perhaps o'brien auditioned, but didn't get it, either marvel told him or didn't tell him but he didn't have his hopes up so he didn't want to talk about it. that would still mean he lied at paleyfest & whatever else, but it could have just been because he felt embarrassed and didn't want to talk about it & his manager knew, so didn't want people pestering him about spiderman. this is a bit iffy because he answered marty mcfly for his dream role, but maybe he did that on purpose because everyone expected him to just say spiderman.
c. o'brien has been telling the truth all along, and there's very slim chances of him getting the role. however, it is still strange that he said marty mccfly is his dream role.
with a, I want to be on board 100% but if I have my hopes up this high, it'll be that much worse if it all turns out to be b.s.
with b, i think he would've answered marty mcfly because he may've been aware of the spidey casting talk (which would mean he lied about never hearing the job) and just didn't and doesn't want his name plastered with spiderman anymore, possibly because he feels his chances are over and he's just too old even though he's still very damn young.
with c, this would just have to mean despite his telling of his love of spiderman, no one ever technically asked him what his all time most wished for dream role would be (before it was denominations of favorite superhero, if you could be a superhero, etc), and that's marty mcfly.