Cate's coat = cota Chait

but...

is Scott's coat = cota Shcott?

And if so, how would I pronounce Shcott?

No -one does not lenite consonant clusters that do not have l, n, r (the 3 amigos) in them. You can have slot/shlot, srot/shrot, snot/shnot, but not scoil/shcoil etc. The reason is down to lenition been about softening of a consonant. Clusters down seem to be softened in groups, probably as the chances of them been realizable are low. Sc could be hch, but others would not work at all, I'd of thought

You could have cóta Scot or cóta Scoit, I suppose

Seán's coat = Cóta Sheáin

Séamas's coat = Cóta Shéamais

Domhnall's coat = Cóta Dhomhnaill

Róisín's coat = Cóta Róisín

You'll notice however that names tend not to be lenited after "d, n, t, l, s", as in the town name "Cluain Dolcáin".

Foreign names are not usually subjected to mutations in Irish, unless they have been around a long time.

quote:

Foreign names are not usually subjected to mutations in Irish

Actually I have seen "siopa Khrugéir", although it looks funny. I think major factor is if the foreign name is easily lenitable. You can't lenite "Zsuzsa" even if you would like to

quote:

unless they have been around a long time

Tá siopa Krugéir (leasainm an Caomhánaigh a bhunaigh an Teach tabhairne) ann le céad bliain.