If you like him, just ask him if he wants to go get coffee with you. Don't overcomplicate it, and don't mix your signals.
Honestly, I'm actually not sure about going out in a group scenario (especially if you already meet in group scenarios). The reality is, when it comes to what women think, guys are dumb. If a guy asked a girl to get coffee, even in a group situation, if he was asking one girl specifically,
nine times out of ten the girl would instantly know that the guy probably likes her, and wants to ask her out (this has happened to me, and is part of the reason why I now just favour a direct approach).
However, if a girl asks a guy out in a group situation,
nine times out of the ten the guy will think she just likes coffee.
I've seen this happen, and there's always an exception, but that's the risk you run when dealing with men
. You may just end up reinforcing in his mind the status quo of the relationship, whereas you might think, having met as a group for coffee, you have 'progressed' into some sort of relationship. Having different ideas on the nature of your relationship is not a great idea, especially after a first 'date'.
I would tend to be upfront, ask him if he would like coffee, go out, chat and see if he cottons on enough to start the conversation himself. If not, I would, towards the end of the coffee, be fairly direct and bring up whether you would both like to meet up again like this in the future, on an actual date. No rush, no strings, no schedule, just see whether, if you went out again, it would be something you both would like to pursue, one step at a time.
And, personally, for a Christian, I think 'hot' and 'Christian' is a perfectly legitimate benchmark to use when asking someone out. Dating is not courtship - you are not engaged, and you do not have to assume the other person is your new spouse! Dating is an opportunity for you to find out whether you could be in a serious relationship. If you find out after several dates that you realise all you like about the other person is that they're hot, then you might want to rethink. But when you're starting out, you don't need to have a completely exhaustive understanding of their personality. Most married couples still don't totally understand each other after years of marriage!