There are obviously many people around with a personal ax(e) to grind vis a vis the Wright Brothers.
I really do not think that the Wrights claimed to be first at anything,sure they filed patents and also probably made themselves unpopular with quite a few people with the legal wrangles - but I do not think there is much doubt about who tackled the question of powered flight in a structured and 'scientific' way.
I personally would not use journalistic articles as a primary source for anything - even after over 100 years of flight they still very rarely get anything correct.
As to 'proving' anything - I cannot do it from where I am at present - and I am always cautious about using internet articles as any Tom,Dick or Harry can write articles claiming it to be the 'truth' (as can be seen by the 2 main doubters on here !)
Were the Wrights perfect ? -No (who is?)
Were the Wrights liars ? ...... I doubt it !
I have been involved in aviation for over 40 years and I see no reason to doubt much about the Wrights 1903 or 1905 flights - they never tried to hide the damage caused during the landing in 1903 and also admitted that the aircraft was unstable in pitch...which is why they redesigned it for 1905...as I said previously - that is development !!
If one reads carefully - the dec 17 flights were on fairly flat ground and not as the op claimed 'glided'...sure they were a little short of power - and as to copying or looking at others engines - there is no reason to reinvent the wheel - technical details are 'copied' much of the time but in the wrights case they would have been dumb not to look at others engines if given the opportunity.Just to be able to design and build a fairly lightweight engine giving 12 hp in 1903 was clever enough !