In 1841 there was at Ballagunnell in Andreas William Monier (30, farmer), Martha (25), William (11), Jane (8), John (4) and Catherine (3). These would be Miriam's people, the Monears of Illinois.
Slightly older, at Ballaceggan in Maughold, was William Monier (35, farmer), with Jane (35), Catharine (12), Ann (10), William (7), Margaret (4) and Thomas (1). These are my relations, the Moniers of Illinois.
In addition, at somewhere near West Craig in Andreas that looked like Croft Cluny Farm were William Monier (60, tailor), Margaret (55) and Edmund (25, joiner). Edmund's baptism gives his mother's name as Margaret Quayle.
Any of these three Williams could be Frances's culprit. Perhaps the newspaper has more information that would enable us to single him out.