There are several issues here. If your invention is part of your job or you are otherwise required to assign it to your employer then it will be owned by your employer and the listed inventors will just be a matter of pride not ownership or monetary value. This is a very likely case.

If it is your IP and not that of your employer, I hope you have disclosed it under an understanding of confidentially. If not you are now barred from filing in the most of the world and have a sort-of one year grace period to file in the US. If your claims extend to anything suggested by your colleagues you may be obligated to state that in a disclosure to the USPTO.

In the US all of the listed inventors on an unassigned patent have identical and undivided rights. They can all license third parties with no need to account to each other. If they chose to have joint ownership under a less horrible set up they can all assign their rights to some entity and share rights in that entity in any mutually agreeable way assuming they have no preexisting obligations.

Inventors are those that have made a conceptual contribution to something that is *claimed*. If it does not belong to your employer and you are controlling the prosecution you can cause there only to be drafted claims to things where you are the sole contributor and you will be the only inventor. If others who you disclosed your invention to decide to file separately on the improvements they have made you will be in a very complicated situation.