your time is likely to be limited - much of the material that is available at the Manx museum is on mormon microfilm and you could do much before arriving - you would then be in a better position to handle any records that may only be consulted at the Manx Musem
To be blunt the use of CAPITALS in a message makes it much more difficult to read (and is considered by most to be the quivalent of shouting) - I suspect many will be able to help you especially is you can give some dates - the name Cain in Kirk Michael was very common!