Is it okay to use +Y restraint in my analysis considering there is a wind load and snow load?

Yep it is okay. Although you should look at the displacements and loads at your restraints for all load cases in case there is lift off or substantial lateral movement due to the occasional loads (such as wind etc).

The type of restraint used in Caesar should match the type of restraint you will be using when the pipe is errected. If it is a shoe sitting on steel then a +y is correct.