One of the reasons to use VLANs is to decrease the size of our broadcast domains yes. Another reason is that we use them to separate L2 traffic, this is useful for security reasons.
By default a trunk will carry all VLANs (1-4094). If you want you can remove VLANs that you don’t want to see on the trunk.
Having more than one VTP server in the domain is no problem. A VTP server is also a VTP client.
When the VTP domain is different then the switch will not sync itself. The only exception to this rule is when you don’t have a domainname…in that case your switch will automatically configure itself with the domainname it sees in the VTP packets.
By default, your switch will be in VTP server mode.
Hope this helps.