Partnership of 3

This is a strange situation, but I would try to describe it in brief.

1. X started the business and worked for one year.
2. Y joined the business after one year and he was involved in the most basic/lowest level function of the business. His work didn't require any special skill, but he has to be there to pick the phone or to talk to the client on behalf of X. It required a lot of time though.

X+Y worked for 5 years and brought the business to a stage where it could be expended further.

3. X requested Z to join the company with one condition: a.) X wouldn't be involved in any activity of the business, and will be a silent partner.

4. Meanwhile Y had separated himself from the business, and was busy in his job.

5. Z took over the work completely and did more than expectations. Work-load increased, and he requested X to give him someone to manage at least the basic/lowest level functions.

6. X called up Y and asked him to rejoin. Y did, and in addition to what he did previously, he was given some extra responsibilities as well.


Now Z worked for 6 months and is now demanding 49% stakes in the company, and wants to keep Y on a salary.
Y is demanding a share, as he was involved in the company since its foundation.
X wants to keep his ownership (at least 51%) on the company, as well as, keep both parties happy.


Now my question is:

1. Is the demand of Z unfair?
2. What should be the ideal breakdown of partnership in this scenario?
3. Any other suggestions?