I'd say we definitely need a third slot pet. Something with a dragonkin attack should work just fine, but anything will likely do as long as Shattered Defenses is up from Ikky. The only way you're going to win with just Ikky and Chrominius, is if Ikky crits on one of its Flock hits.
Clarx, a comment about your comment: Ikky is not a problem.
The problem is the limited Boss buffs they come up with and re-use, which makes Bleed & Stampede such an easy answer, and often the only answer. In 8.2, I believe they have deliberately played into this to make the dailies easy. As in the rest of BfA, they seem to want to tempt more people into pet battles with rewards that can be achieved using just a couple of pets and with easy battles.
Look beyond your own strats, and you will see many other ways they can be done. I went in with a Sen'jin Fetish and Infected Squirrel, which do everything except one on Mechagon quite reliably and nearly all in Naz. But it's still a Bleed & Stampede strat.
If they nerf anything, it will be the more general Shattered Defenses debuff. But then they have to reckon with the bosses like these that are challenging or impossible to do without it.