That third link you posted is probably some ignorant disciple and/or malicious actor deliberately mistranslating what was said by Guru Siyag to get people politically involved. I strongly doubt Guru Siyag would encourage his students to get involved in politics, given what he has said in the past about fake spiritual teachers and money.
As for him being the next prophet (whatever that means), I'm not qualified to make any judgement. However, I can speak with confidence regarding my experiences so far with the practice, which I've been doing on a daily basis for the past 5 years, and I can say that I've benefited tremendously both physically and mentally.
Prior to getting initiation from Guru Siyag, I had numerous alignment issues in my shoulders which were frequently causing me pains in upper back and neck area, after I began to experience the spontaneous kriyas as a result of the initiation, my alignment problems gradually went away. Years of these spontaneous kriyas and pranayamas have completely transformed my body and consciousness in ways that will be impossible for me to describe.
And by the way, I never paid a single dollar to receive this initiation!! There are countless so-called "legitimate" Shaktipat gurus out there who charge people thousands of dollars for their retreats and run grotesque cults that exploit desperate people. Guru Siyag openly gave his initiation free of charge because he understood very well that people who suffer physically and mentally should not be asked to pay. He is the only Guru I have found that did not run a spirituality business. I would consider this to be one of the criteria for an Enlightened being.
The samsaric beings/gurus that you refer to are the ones charging big $$$ for Shaktipat, that is if they can even do it properly!!!
I would also like to share something else. I have received numerous PMs from people on this forum who told me that they tried getting Shaktipat from other teachers but without any results. And when they tried the free initiation from Guru Siyag, they immediately began to have very profound experiences.
EDIT: for anyone who wants to learn more about the purpose of these spontaneous kriyas, please read this - https://ourlightbody.com/index.php/part-iii-human-metamorphosis/chapter-6-all-about-kundalini/what-are-kundalini-kriyas