You can definitely pull off cross harp for a minor key, but you have to put a little bit more thought into it. Just playing your standard cross harp blues licks will sound janky if you aren't careful to hit that flat three consistently, instead of that major/minor "blues third."
SNIP
how about just stickin with 2nd position on an F harp. you can use lo lo F, lo F, and regular old F. I am sure there's lots of decent choices though. If it's more of a BLUES groove - I would likely go with that... especially those two chord grooves that let you run in some interesting directions.