I also agree with what they did with Galactus. He was traveling in a giant cloud across space. You clearly see him inside the cloud as he's about to devour the earth.
Listen to the commentary. Tim Story said he knew this was gonna lead to a Silver Surfer spin-off so he didn't want to give everything away in FF. Come the Silver Surfer movie, we will see Galactus.
As for Deadpool, yeah, that was kinda ridiculous. It's plausible, given Deadpool's abilities, that the Weapon X project can do that to him. And if the Deadpool spinoff takes place after XO Wolverine, then I'm sure they're going to undo everything they did to him.
They'd have to in order to get Ryan Reynolds back to star in it. Reynolds only played Wade Wilson. Weapon XI was played by Scott Adkins. And also, a movie about a guy with his mouth sewn shut... doesn't make for an interesting movie if the main character is silent the entire movie.