i think non blender tutorials will be helpful for blender users too as long as you know the basics because 3ds max tutorials can help in hardsurface while zbrush tutorials can give you tips and tricks for sculpting maya ones can give you help in animating and unwrapping there are always tips and tricks that can work in both software seriously i learned to model some stuff like faces and creatures from 3ds max tutorials while i learned detailing from zbrush ones
and lets get to second topic
cylinders and circles tbh these shapes will help you more in modeling that cubes they are round which gives the a z and x dimension
i made this using cylinders this is low poly i applied shade smooth and couple of loop cuts for smooth roundness
so yeah cylinders are better for creatures and cubes for anything non organic i think beginners should not use cubes for modeling creatures nor subdivision modifier