If they blow something up and have plausible deniability long enough for the story to cycle off the front page, then the EU won't do anything. Especially if they wait a year or two before they do it.
TF's theory is interesting and would make some sense, but there is no proof of it. Israel's neighbors shoot missiles at them all the time, including Iran's allies. This isn't unusual.
Waiting a year or two, would be a "retaliation" attended by a lot of patience. In the meantime, there will be a huge disconnect between Iran's rhetoric and what they do. That kinds of reminds me of Trump (in his case thank heavens). And if Iran denies that it was the perp, then how can it ever claim that it retaliated at all?
As to a lack of evidence, well yeah. At the moment, we are in the idle speculation mode. But I find this more interesting (and perhaps important), than speculation and flame wars about how many seats the Pubs will lose in Congress, based on stuff that to me, lacks statistical robustness this far out, but that is just me.