Here is the reason it is not possible UNLESS you sew the pocket shut.
On just about embroidery machine I know, of there is the bobbin arm that has to go under the area of embroidery. Given the fact that it is almost impossible to even get the arm into the pocket after hooping let alone get enough slack keep from binding beyond the geometry of the design.
The only way to do this is remove the pocket from the shirt sew it flat and resew it to the shirt.
In general unless the custy is up for sewing the pocket shut through the shirt run like hell from a job like this.
BTY basic rule if you can't fit a standard soft drink can in the pocket and have at LEAST 50% of the can width in slack North , South, East & West of the design it will never work.
mooseman