Will you be living in Scotland? If so then great, if not then your child is going to grow up wearily correcting misspellings and pronunciations. If you're not living there then maybe a Scottish middle name would be better.
Seòsaidh is quite nice, but it is Joey rather than Joseph. If you want to use the full name in Gaelic you have three spelling options: Seòsamh, Eòsaph or Iòsaph.
I really like Beathan, as well as the Scots equivalent Bean (pronounced Bay-an). Folks will always try to pronounced it as thought it were English though, so perhaps better sticking with Gaelic if that's your chosen name!
Sorry, Jakey is absolutely right - it's Joey not Joseph. I think that because I know several women - and no men - named Joey, I sort of automatically blank out Joey when it comes to men's names, and think only of Joseph, IFYSWIM
bigbadgeorge, have you considered Seoras? Saw the George in your name. Slightly more commonly known name but along the lines you have mentioned above. Love Beathan too but appreciate the confusion with Bethan. I think if you explain a pronounciation to folk they generally get it right from then on tho'!
Thanks for everyone's thoughtfu replies! Yes we live in Scotland. I'm English but my OH is Scottish and seems very set on a Gaelic name. Once I realised how to pronounce Beathan I liked it BUT I do think people will pronounce it like its writen in English which sounds awful! I really like the seoras suggestion, I'm off to suggest to my OH now.....
Harris and Ruaridh are very popular where I live. I have never heard of your other two names. Think he would be forever correcting spelling and pronunciation. I have a name like that and you do get fed up of always having to spell it