the 'dual' baptisms are most likely the IGI ignoring the comments - eg in researching Andreas PR's there were several 'baptised in Kk Bride'. another in Lizburn Ireland - the PR was noting those ordinarilly resident in the parish (several errors are in the IGI due to obvious misreadings of the PR by the 1911 transcription though the majority are due to the misreading of the 1911 transcription by later researchers).

I read the name as Rothmell - he + Cath appear in 1703 Castletown composition book (you can locate his property) - see www.manxnotebook.com/towns/castltwn/1704_cb.htm
(he also appeared as a witness to a will I transcribed)
He was a gunner at Castle Rushen in 1700 (a well paid + highly skilled job - reflected in his property holdings) - if you look at www.manxnotebook.com/methdism/chapels/castltwn.htm you will see mention of his nephew

He was there in 1673 as he was censured for something to do with church (non payment of cess ?) I also have a ref to Archd will 1695 #55 bk 2 Malew of Charles Rothmell: wife dead and wrote a will; son John, dau Ellin executrix.