It is a bit hard to see the details. The tree is in the way, but does the garage section have a front facing gable? Are the shutters built in or attached.

I think I would take off the porch railing and beef up the posts. The porch railing seems to closing the space and there doesn't seem to be a need for it.

I would not build over the garage unless you need the space.

The garage section does have a front facing gable. It already has a second floor to the garage, but it’s only accessible from the back of the house and it’s only for storage. I like the idea of revamping the porch! I’ve seen a “4th floor” on split levels and we were considering that too. But I didn’t know it that would be strange.

Not sure I'd add to this, but make better use of the space you already have. A second floor that is only for storage is a waste. See how you can reno the accessibility and make use of that area.