there is an index of wills on www.iomfhs.im (follow research link) - these give year & LDS film number - you can borrow the film and read the wills.
Likewise the official copy (which is generally an excellent transcription) of all parish registers is also available on LDS films - I don't want to sound unhelpful but I strongly suggest that you personally view the various films to avoid possible misunderstandings or get someone to take photocopies of the relevant pages (you stated that you had communicated with someone on Island who would have easy access to Museum).