Maybe "God" is well defined in the context of analytic philosophy, but if not you could consider starting by asking what they mean by "God". You could then ask a variation of 1 or 2 (they seem identical?) and how their response would change with other common definitions of "God".

This would hopefully prevent wasting time due to different use of words or misunderstanding their position.

In a similar vein you could ask what would be sufficient evidence for them to believe something. (Maybe this is already specified by the analytic philosopher part?)

Are you going to talk to them one on one or in a group? If it its a group, to me it seems, a likely failure-mode is them discussing the points that they disagree on which are likely to presuppose the the existence of God.