It's true, you may not be able to make many of the changes. But this process is intended to be instructive with respect to the general matter of fit, and future purchases. Maybe next time, you and others will know to avoid a jacket that requires impossible modifications.
Still, you probably could fix it a bit, if it's really worth the time and money to you. I bet a good alterations tailor could let out the chest some, let out the hem to make the jacket a tad longer, and move the pockets. As far as the pockets go, it would be ideal if you could move them down and in, but the pattern-matching will be all off. I disagree with Manton that moving them inward should be the priority--downward is more crucial, particularly if you have the hem let out.