I view the possibility of your number one to be nearly nil, but one should never say never. Genetically, no "goat" will ever slip through, but some slip up in a purifation procedure, coupled with a slip up in quality assurance, coupled with a newfound issue with some fragment of goat protein that has never caused an issue before...
I think a more realistic competive risk will likely some day come from chickens. We may be able to do some real analysis if GTCB ever decides to make biosimilars like interferon 2B, or GCSF, or even EPO for that matter.
I think a bigger risk than either of those is threat of continued improvement in cell culture expression eventually narrowing the cost gap to a point where it may not be a big deal. Its not ten years ago anymore.
I wish I had more money to invest here.