Feature transformation possible at selected features or only at all?
Either can be good or bad. It's not necessary to apply the same transformation to all attributes; but if youe attributes differ that much, you likely have some major problem anyway.

It depends on what you want to achieve what is appropriate. Try to approach it from having to explain your choices later. Can you argue why you transform the data this way? What is the statistical meaning of this transform for your problem? Here you'll quickly realize that with mixed data you can't really argue much - your results are based on guessing, not in a sound model.