Yes, to all of the above (thanks again H4O).
Even if the "soul mate" is "reduced" to the perfect meshing of needs or wants, it is still a powerful (and interesting) relationship.
I have had relationships where the "connecting" has led to "fusion" and a disinterest in participating with others and the rest of the world - and then there have been relationships where the "connecting" has inspired a reaching out to others and the world.
I think it may be unhealthy to become so fused with another that the outside world becomes an irrelevant distraction; but I am intrigued by the relationships that inspire to greater reaching out and engagement.
Although my goodness the painful bliss of passionate desire is something to behold...