f the content had already been written, then why would they have adjusted it to the current companions and then later rewrite those to be inclusive? They've never said literally that the existing companions would be SGR capable and I very much doubt that they're going to do that, it just doesn't make sense. Adding new companions with a story update makes much more sense.
That's just another thing we can't get an answer on - they say they've "known from Day One" who it would be, provided "it makes sense" which may mean some Classes get new ones as the SGR option.
However, "we want to do it right"... plowing through to 50, then meeting some brand-new sidekick and racing through their story arc on just one planet (assuming it's in the Makeb patch)... I don't know, that doesn't seem like it'll be up to par with the existing standard.
"Everything's still on track, this year" - in the absence of any follow-up info, that's feeling more and more like "What we told you was true.. from a certain point of view." will be the gist of a Yellow post come February.