If the boots fit then buy them. IF they don't, don't buy them unless you are a glutton for punishment. Had a friend go to Russia and only rock shoe size they had was an 8 and he normally wears 11. You do what you have to do sometimes. =)
Don't need a front clip for WI3 ice. Even WI5 you don't need a front clip. Its nice to have, but not needed unless long stretches. You don't seem to be doing that.
You can go "ice climbing" in tennis shoes if you wish. Be a might hard on your ankles, but you wouldn't be the first nor the last.