I don't always feel comfortable playing outdoor, I'd feel even less comfortable playing in a skate with no cowling. A frozen puck combined with cold feet and cold skates, a direct shot at your skates hurt like a sunnuvabitch.
Anyway I'd recommend a long-sleeve shirt, a thin balaclava like the football players use. Otherwise anything else is at your discretion. Also, get your skates sharpened after every outing. Outdoor ice can be very hard on your steel with bare spots, dirt, debris etc.