Re: Is there any requirement to be compliant with IEC 62304 while implementing ISO 13
That's pretty much a trick question.
The short answer is no.
But let me relate my experience. I cited compliance to it in my Technical File. My NB at the time, then, required that I have an independent lab assess compliance (the NB said they could do it but it would delay the review and cost substantially more).
Another client with a different NB cited compliance in their Technical File and the NB accepted it without the added review. So I don't know what the best approach is.
It *is* a harmonized standard (although only the :2006 version, not the :2015) so compliance is, well, expected to be the best route. In the US, FDA cites the :2015 version (and the :2006) version as consensus standards.
Since you mention outsourcing, let me relate one more bit. Two NBs that I worked with have both cited software development as a critical process. If the software developer is NOT registered to 13485, the NB will likely require that the developer be audited (at your expense). So if you're outsourcing software development, it's probably best that a) they be registered to 13485; and b) they comply with 62304.