The most common reading of 怜, when occurring as a girl's given name, is Rei. But it's impossible to say for sure without furigana. Also I think the norm for Danbooru is to preserve original name order. So "Shiraishi Rei" might be slightly preferable.
I'll do it!Are you saying you'll be a decoy...?Rai ShiroishiThe only question is, how do we lure him out... right?