Thank you for contacting Ireland Reaching Out. I'm glad to hear you are visiting Belmullet and have relatives to meet while here. If I can meet with you I will.
I hope you can visit Ionad Deirbhile, the Heritage Centre and Turas Siar both places dedicated to the History and Heritage of the area.
As regards your research have you looked at the website Blacksod Sailings. Quite a number of people from this area emigrated to St. Paul, Minnesota which you mentioned as Bridget Lavelle Ginnelly's destination in 1904. Very likely she had relatives who emigrated there in previous years. You can search this website by Surname followed by US City or State. You should email the Heritage Center near to Blacksod to have them look at the ship's manifest for names you see as possible links.
I believe that Death Certificates in the US have both parents names on them. Have you seen or obtained Bridget's Death Cert?
I will email you directly with contact details for those places to visit that I already mentioned.