Can you legally marry 2 people in wi without being a an ordained minister or justice of the peace.

So here is the law:
765.16  Marriage contract, how made; officiating person.
(1m) Marriage may be validly solemnized and contracted in this state only after a marriage license has been issued therefor, and only by the mutual declarations of the 2 parties to be joined in marriage that they take each other as husband and wife, made before an authorized officiating person and in the presence of at least 2 competent adult witnesses other than the officiating person. The following are authorized to be officiating persons:
(a) Any ordained member of the clergy of any religious denomination or society who continues to be an ordained member of the clergy.
(b) Any licentiate of a denominational body or an appointee of any bishop serving as the regular member of the clergy of any church of the denomination to which the member of the clergy belongs, if not restrained from so doing by the discipline of the church or denomination.
(c) The 2 parties themselves, by mutual declarations that they take each other as husband and wife, in accordance with the customs, rules and regulations of any religious society, denomination or sect to which either of the parties may belong.
(d) Any judge of a court of record or a reserve judge appointed under s. 753.075.
(e) Any circuit court commissioner appointed under SCR 75.02 (1) or supplemental court commissioner appointed under s. 757.675 (1).
(f) Any municipal judge.
So the answer would be:unless you fall in to these catagories above you can not officiate.  But they can THEMSELVES through the “mutual declarations that they take each other as husband and wife” according to the traditions of their faith.