I'll try to help.
a) is a sequence of genomes considered coded information? if not, why not?
Yes it is. Although "a sequence of genomes" isn't exactly the right way to phrase it. "A genome's sequence" might be better. A genome is the entirety of an individual's DNA, so a "sequence of genomes" would imply something like placing multiple DNA sets in certain orders, which I'm sure isn't what you meant.
DNA is encoded in several ways, the most basic being "the genetic code", which maps triplets of basepairs onto specific amino acids.
b) if so (you can guess where this is going), does mutation/selection ever add to that information? if that is an irrelevant question please explain why.
Mutation can indeed add to that information. They can also remove information, or alter information without increasing/decreasing it. It depends upon what kind of mutation has taken place, there are several varieties.
Selection is a bit trickier to give a direct answer for, because it affects information distributions within the population, and thus in order to give an answer you'd have to specify which information measure you're asking about at the moment (e.g. total information size, information diversity, etc.). But selection can also increase, decrease, or change information depending upon circumstances.
c) if genetic sequences are information, and mutation/selection does not add to it (i'm not assuming it does, answer (b) first), does that go against abiogenesis which has to starts out at the absolute simplest level (non-life)? (i know, evolution and origin-of-life are two different things, that is not what i'm asking)
Not a problem, since mutation/selection can indeed increase information, and fine-tune what information is present.