New player.
Are you planning for pve or pvp? I’ll try to answer some of your questions, assuming you mean pve…
1. Really whatever you find the most fun, open world pve is easy and any weapon will essentially work. Greatsword is the most common as it is pretty fun to play and you can tag mobs from far away.
2. Again, whatever you think is the most fun. The best support is good damage, with some utility i.e. reflects, pulls, interrupts, whatever
3. Best builds for what? i think that people generally run phantasm builds for pve.
4. No comment
5. Sure, mesmer is my favortie class and I like to think it is a good character. It can add some decent damage and provide excellent utility. I think all classes are pretty boring when starting out, but once you get to a high enough level you really start to get a feel for the class and can decide if you enjoy its mechanics or not.
4- What type of WvW do you see yourself doing? Solo roaming, Havoc Groups, organized guild zerg?
There are mesmer builds that are ideal for each circumstance.
But that can be said for any class in game—they all have builds that highlight their strengths in certain environments.
There are so many ways to play a mesmer and that’s why you are going to see many people tell you “Whatever is fun”.
Hey man, Mesmer is a very fun class once you get the hang of the shatter mechanic.
Check out Osicat’s guides to learn more about Mesmer!
https://forum-en.gw2archive.eu/forum/professions/mesmer/Guide-WvWvW-Pve-Shatter-Cat-2014-04-23/first
Personally, I switch between Shatter, and Interrupt Builds (shatter 0/4/4/0/6) and (Interrupt 2/4/6/2/0) but, it would be a good idea for you to learn how shatter works. It IS the class mechanic after all!