What pitch roof do you think this is?

[inveresk]

Lou, the roof pitch would remain unchanged. To change the door height, I would enlarge the whole image to realise a door height of 6'8". Thus, both the horizontal dimension of the roof and the vertical would be increased proportionately, giving the same final pitch.

 

[jimmysisson]

Another thought is to your snow situation. Though the added-on look of the shed in your photo is handsome, snow sliding from the upper pitch can stall when it reaches the lower pitch of the shed roof and sit there. That's fine if it melts, but if you keep getting more you can end up with a big pile. Why not build the side sheds right away and use trusses that make the thing all one, slightly lower, pitch? Keep your shed eave walls at 7' or even 6', to keep the pitch high enough; you'll find plenty of your stuff will fit in there. You'll never regret the extra covered storage space after the first few payments. Unless your BIL has some stuff to store and no shed...
Jim