DY: Well, it’s not Pshat but I would be most comfortable if MeIkara Savar was referring to the Ovdei AKU”M. I agree the most simple is that Chazal were in error of the OA”Zs’ intentions at first and then corrected themselves, but that feels wrong, doesn’t it? So I dunno. I would think my second option is the best-that Chazal knew these idols were worshiped but didn’t think what they did constituted worship because they didn’t view them as deities, just a statue representing Listim or something like that. And then they realized that they weren’t just viewing these idols as representing Listim but that they were actually gods.
RSB”G presumably holds something else entirely. Namely that if they went to the extent to be so precise in this Pesel as to have it hold something, it’s because it’s meaningful to them and therefore presumably Ne’evad. Which makes sense that the Gemara asks what if he’s holding something very not respectful.
I was assuming like Rashi and the other Rishonim, yes. My Pshat has a bit of trouble with Rabbeinu Tam. I’m not saying he was mistaken (though I haven’t thought it all out; it could be that that’s the only possible outcome), but he is a minority opinion in the Rishonim.