This really is off topic here, but I believe I need to set the recoded straight here. The paper linked above overstates the truth of the matter. I'm not completely sure why Einstein tend to be so much more recognized for his contributions to Relativity than the others working on the problem. I don't see how he can really be blamed for that.
I know Wheeler and Taylor give recognition to Poencare and Lorentz. There was probably a lot that people lost track of shortly after Einstein published his General Relativity work. Its absolutely correct that these ideas do not arise in a vacuum. Advances such as these are a product of the culture from which they arise. It´s not clear if Einstein actually saw the work of Lorentz and/or Poencare. AFAIK, the three theories are mathematically identical. The difference in how Einstein perceived the model was really the significant distinguishing characteristic. But the paper you provided indicates that Einstein acknowledges that fact.
It´s been quite a while since I looked at these topics, but IIRC, Lorentz was addressing a somewhat different problem than was Einstein. Lorentz was trying to explain the measured invariance in the speed of light. Einstein was trying to explain the problem of Maxwell´s equations as viewed from an observer traveling with the same velocity as a light wave. It´s seems possible that Einstein may have encountered Lorentz´s ideas indirectly, and used them as a starting point for his own derivations.
We cannot say that Einstein actually used either Poencare nor Lorentz´s work in writing his own theory. His work is certainly not, strictly speaking, plagiarism of any known previous work. If he had used either Poencaré or Lorentz´s work directly as a basis of his own, they he certainly should have provided references, which are absent.
I´m fairly certain he arrives at many results concerning Maxewell´s equations which were not present in the works of others.
The comments about e=mc² are those of a person who does not understand the topic. I am not aware of any derivation prior to Einstein´s 1905 paper.
The derivation has always left me a bit puzzled because it seems to indicate that e = mc² is only an approximation. There are other means of deriving the equation which do not, IIRC, have fourth order terms. But I´ve never found time to investigation this.
I believe Einstein may have peeked a bit more than he acknowledged, but he really did some groundbraking work. There are probably many people whose ideas made their way into Einstein´s work without getting credit. But, to some extent that is the nature of intellectual advancement. Ideas are often transmitted in informal ways and converge in the mind of a single individual who has the ability to express them. With a field such a physics, a person really dosen´t need more than the basic concept of how something is derived in order to reproduce the results. That limited amount of knowledge can be transmitted informally and verbally.
Another point to bear in mind is that Einstein´s wife also had a degree in physics, and may well have helped with his worked, or introduced him to ideas that he did not directly get from reading the works of others.
"From October 1928 the two largest regular contributors to the Nazi Party were ... of Jewish faith, and one of them the leader of Zionism in Germany." Brüning, 1937