No. The activation point on Topre's is a completely independent mechanism from the tactility. But to be sure, lemme plugin my HHKB in and test...
Yup. You can ride the activation point. However, it's pretty much right in the stiff resistance point of the downstroke, so you'll probably feel the tactile bump a few times. However, it being 45g (on the HHKB at least), it shouldn't make a difference.