Beginner advice: Set or individual?

[Virtus]

The 17.5 Morpheus is a great choice! Word of warning though - you will quickly want more Morphei ha!

They also Barlow really well so if you picked up the 12.5 and a 2x Barlow down the road it would essentially give you the 9 and 6.5. That is what I did until I found a really good deal on the 9 and 6.5 used.

Definitely don't be afraid of buying used; I've found it a great way to test equipment out and most stuff is easy to move again if you don't like it or just want to try something different.

In regards to zooms - my first EP purchase was a Baader Mk IV 8-24. I couldn't imagine why anyone would want to fuss with fixed focal lengths when "good" zooms were available; I quickly learned that I much prefer the wider FOVs of the Morpheus and APM UFF. The Baader zoom isn't a bad EP, and it was a huge step up over the MA EPs that came with my first scope, but I find I hardly use it now. It's great for a quick grab and go session or showing stuff to friends and family though so I will be keeping it. I find that the range from 20-24 is useless, it provides almost the same TFOV just at lower magnifications. The range from ~13-20 is better but still not great and then from 8-12 it finally starts to open up and becomes really enjoyable. With all that being said I'm a bit torn - I was going to recommend getting a budget zoom like the Celestron or Svbony just to try it out as some people absolutely love the zooms but with those the FOV is even narrower across the range... 

Switching out fixed focal length EPs as you observe isn't the burden I thought it was going to be.