The first thing I would say is don't get certified for a restaurant chain unless your local law requires it. Most certifications are customer driven and it is unlikely that many of your customers would have ever heard of BRCGS or FSSC and it costs a lot to get certified.
That said, there is a lot in these Standards and others that you can take and modify to fit a hospitality business. You can use some of the building fabric requirements in designing the construction and layout of your operation.
Don't though go over the top, take the parts of the Standards which you could and should manage to begin with eg., your risk assessments and staff training.Keep your record keeping to a minimum, temperature checks, training and stock rotation for instance. If you are in a small restaurant chain you are probably going to work with a low number of employees and they are not going to have a lot of time to do lots of paperwork. Invented results are worthless and may cause bigger problems.
Introduce an appropriate level of audits, primarily hygiene and GMP