1. None of the DBZ characters have shown anything resembling defense against Telepathy. The Saiyans are resistant to Mind Control, but that's far from the same thing. Magneto has some pretty powerful defense against Telepathy, but Xavier still managed to mindwipe him with a telepathic spike. That's exactly what Emma Frost could do to the DBZ characters as well.
2. When, exactly, did I say that Namor can compare to almost everyone? What I said was "Namor could easily take out some of the less powerful DBZ characters". Which is definitely true.
3. Let's say then, as you say, Vegeta blows up the planet, while the Surpreme Kai and Goku Teleport all their allies to safety. There are several people below Silver Surfer's level that would survive that, Blue Marvel and Void among others, to use an earlier example, most of the heroes in Marvel would also be safe 'cause, you seem to forget, that Marvel has several characters with Precog. abilities. So now we have earth destroyed and all the heroes(and possibly villains) pissed off, at this point people like Thor and Hercules are going to get the Sky Fathers involved. I.e. the DBZ characters get willed out of existance. A best case scenario for the DBZ'ers, is to take the heroes on one(or a few) at a time, that way they survive the longest.
Also the Telekinesis shown in DBZ is relatively low level. The best telekinetic feats in DBZ go up to a few tons.
And, Immortality is well within the powers of the Dragon, yes, but Unlimited Energy is not, not unless it's creator has/had infinite energy.
Finally, which "old feats of someone that are no longer valid", have been brought up so far?
In canon stuff, staring with the oldest, Frieza killed Krillin with a telekinetic crush, he also mentally threw a large chunk of mountain towards Goku, Frieza killed Krillin with a tk crush move. I can name a lot more examples, If you doubt please refer towards the manga, and or anime. It is 15+ years old I am sure you have seen them.
You mention that Magneto has great telepathy defense and yadi yada, but lets see how Prof X would do vs Thanos or someone just plain better, he would do anything. This is just that case, Prof X doesn't have the power behind his mental powers to do anything to Goku.
Vegeta withstood a magical/telepathic assault just to get more powerful, Goku even mentioned that he think vegeta so weak to get controlled.
Babidi, tried to "telepathically" control Vegeta to kill Supreme Kai and Vegeta did not do it. He shrugged it off, if that is not telepathy defense I am not sure
Also you are assuming that Sentry and everyone would be able to sense the planet blow up. Nothing will stop Goku from teleporting there, blowing up the planet and leaving. I know that won't happen, but you act as if Goku wouldn't do anything to them, when you and I BOTH know that plenty of weaklings have gotten the best of everyone you have mentioned.
Dr. Strange defeated Shuma-Gorath, but yet lost to Hulk, even had his hands broken.
Surfer opens Black-Holes but gets punched by The Thing and Hulk.
its all relative