If you really need to, you can always use the Jungle animation as an attack (this is what I've done with worker units in the past). I shall probably try to do a shotgun attack for the Prospector at some point as well, and maybe one or two others will get attacks too. But it does mean a fair bit of extra work!
no, clean pollution is a seperate animation (as shown by Wyrm in the Modern Worker)
Ah, irritating irrigating....Yeah, there is only irrigate in the ini files...