Re: Spiderman in the Avengers "world"?
First off since there has been a push for some acknowledgement on a corporate level, and was going to happen had time constraints not been an issue. I actually think there would be a good chance someday references to the sony franchises will be made in the MCU, but it would be subtle and not cameos or full out crossovers like some might want. An oscorp reference in an MCU movie. A Shield reference in a spiderman...
The only way there is more is if Sony really does decide to close the entertainment side of its business, or spin it off into a company Disney could buy out.. they have had such rumors over the last five years for business reasons, but barring that I just don't see anything more than an easter egg that really means nothing coming anytime soon.
As for the Fox labels... The higher ups have had some falling out with Marvel, im not sure they will ever give up Xmen. If FF bombs again, maybe Marvel gets that back, but they will never give up the Xfranchise and probably never acknowledge MCU
Isnt it past your bedtime?