I pluck hairs around my stoma, but only those that grow close. If there is hair outside about 3/4 inch away from my stoma, I just leave it be. Lucky for me, I am not overly hairy in general and I'm rather thin-haired at best on my chest/stomach. Full head of hair up top though, no sign of hair loss so go figure. :)
In regard to pulling hair, I use a fine tweezer and pull close to the skin to get the entire hair. They all grow back no matter what, and I'd guess I pull them about once a month.
I tried my electric trimmer that I use on my beard there once, and after one nick of the skin, that was that.