SEE is only a problem with reduced charges of slow powders in LARGE cases (think belted magnum/.50 cal). Subsonic loads with pistol powders? Heck no. You DO, however, need to make sure you don't stick bullets in the bore, then follow it up with another shot (especially with jacketed bullets), and you damn sure need to make sure you don't double charge. If you have ironclad safety procedures while reloading, and you have some basic knowledge, it's not dangerous.......kind of like reloading in general. There are just some new rules to follow, since you are trying to achieve a different effect.
Bottom line: Cast bullets of a soft(ish) alloy, like air-cooled pure clip-on wheelweight alloy, over a small charge of fast-burning pistol/shotgun powder are safe provided your barrel isn't five feet long. In a similar cartridge I load about 7 grains of red dot under a 160gr cast bullet. I haven't chronographed it, but I'm sure it's subsonic, and I've fired a couple hundred of these without incident from a mosin 91/30. Possible? Yes. Safe? Provided you know what you're doing. For the new reloader? Probably not, but I was doing it within 6 months of making my first reloads.