Don't know much about the bookbinding/printers or Nixon, Jarvis or Foster what came first etc..
I have found a notice which stating - Walter Amos Foster (trading as Jarvis & Foster) of 118 Pennant Crescent Bangor was "Foster"
Looking at the old adverts, the oldest (in appearance) appears to be Jarvis & Co at Lorne House. The 'newest' Jarvis & Foster (rear of) 204 High Street (R.T. Jones proprietor).
The other Jarvis and Foster adverts site the location as Lorne House, the only Nixon & Jarvis advert says Bank Place - but I suspect that is the same place.
Given that I guess the business went... Jarvis, Nixon & Jarvis, Jarvis & Foster.
Their first appearances in the North Wales Chronicle appear to be:
1869 Messrs Nixon and Jarvis
1889 Messrs Jarvis and Foster