Yes, Stratovarius are no Malmsteen clones musically although that element is present, but Tolkki is definitely an Yngwie disciple - and he's far from the only one. I mean, I love Yngwie, too, but all these clones out there don't do it for me because none of them can touch the original anyway. As for...

How original were Britney Fox/Warrant/Danger Danger/Helloween/Tyketto/Winger?

I think they were fairly original - more so than Sonata Arctica at this point - with the exception of Britny Fox who were basically bad Cinderella. Helloween certainly have developed their own thing and are/were actually a huge influence on the likes of Stratovarius, HammerFall and that whole Euro melodic speed/power metal retro movement. I think the thing that brought down Warrant, Winger and the whole pop/hair metal was the incredible inbreeding that was going on. Everyone started to use the same producers, outside writers and probably hairdressers and makeup people, too, thus blurring the lines even further. And of course then all the second and third rate hair bands were getting signed and flooded the market with music no one really needed because it was more of the same, only worse. That's why it was so easy for alternative to take over when it did - people were sick of the same old same old, and unfortunately, the good bands got flushed down the toilet with the Roxy Blues of this world.