The NQ is a CPL requirement, not IR. There is nothing stopping someone with a colour restriction doing an IR, simply that it can't be exercised at night.
I did the dual thing for my CPL night; I logged P1 and the instructor was a safety pilot. There are loads of instructors (and examiners) in GA with a colour restriction... They all got their CPL like this.
I eventually managed to pass a Spectrolux test and get a clean medical, but during my research at the time I found there were only 2 things you cannot ever do:
1. Carry fare paying passengers on a public transport flight.
2. Exercise your NQ.
All licenses (except ATPL due constraints above) and ratings can be attained with a colour restriction.