And, particularly, why ask so many different (irrelevant) people? You are taking an opinion survey. And opinion surveys don't mean much. At the end of the day, the only opinion that will matter is the FA, the lead FA, and the pilot. It won't mater what you were told on the ground, and it won't matter what you were told on the phone. The folks on the plane matter... no one else does.

My approach would be to check the electrical load. The heat likely will overload. Without the heat, I'd GUESS that it works. And I'd GUESS that the rating is for vibrating and heat together. So, my next step would be simply to plug it in and try it. Assuming it doesn't annoy your set mates, just try it. The worst thing that can happen to you is that it can draw too much power, which MIGHT annoy the guy running his laptop next to you. But don't sweat it, just try it. You can't get arrested. You can't crash the plane. Just try it.

If someone doesn't like it, they can tell you. If you have reason to THINK they might not like it, then politely and simply ASK. But otherwise, keep your mouth shut and just do it. If the FA doesn't like it, they'll let you know.

If you ask enough people in advance a question that is not written in policy ANYWHERE, the mathematical odds are that you will get someone to tell you "yes", and someone else to tell you "no". Don't ask. It isn't binding anyway.

I once traded my exit row seat for three empty seats side-by-side cuz the guy in the empty row wanted the power port. I took it. Then, when I wanted the power port too, I simply ran an extension cord up two rows and had the guy plug it in to the other power port. I got power AND three seats to sleep on for a transcon. I could have got lots of opinions asking, but instead, just did it. Enjoy life!