Posting a "$100k-$150k for X" position completely fails to communicate this. Intentional or not, this comes across as either you don't know what you want, or you're trying to sneak in extra responsibilities to the position without having to pay for them.
And I'll reiterate: $50k is a lot to pay for a "nice to have".
I'd say you need to really think about whether you need Y and Z. If you don't, just post a "$100k for X" position. If you do, post a "$150k for X, Y, and Z" position". If you must, post both--at least that's honest. But it would be better to come to a firmer conclusion about what you need before hiring.
And I'll reiterate: $50k is a lot to pay for a "nice to have".
I'd say you need to really think about whether you need Y and Z. If you don't, just post a "$100k for X" position. If you do, post a "$150k for X, Y, and Z" position". If you must, post both--at least that's honest. But it would be better to come to a firmer conclusion about what you need before hiring.