Canon 1D Mk IV + Sigma 500 F.6 + Sigma 1.4 Convertor, will it auto focus?

Will the following auto focus at f8 .... Canon 1D Mk IV + Sigma 500 F.6 + Sigma 1.4 Convertor, or does it have to be a Canon 1.4 convertor ?

Thanks

It will AF with center point only at F/8, but it has to be the Sigma f/5.6 prime. If you´re talking about the 150-500 f/6.3 or 50-500 f/6.3 at 500mm, it won't.
And I think Canon TCs only attach to Canon lenses. AFAIK you have to have a Kenko or Sigma to attach to Sigma lenses.

I found that my Sigma lenses work better with the recommended Sigma TC. Although, I have no complain against the Canon TCs either.

canon mk2 tele 1.4x fits and works on some sigma lens

Yes, it will AF, I have tried it. The Sigma TC might work best but I also tried the Canon and could not see the difference, both worked well!