Hey Vear! Welcome back!
The group comp that's kinda the meta right now is SK/SHM/BRD/BST/ZERK/ZERK(or a rogue). For your group, the big issue I see is the lack of CC. You have a slower, but no real mezes. So, if you wanna work toward the "meta comp" then I'd drop the cleric for a bard or chanter. I started my return to EQ like 2 months ago now, I started with SK/CLE/ENC/MAG/WIZ/Zerk and the guys here recommended either the comp above or to swap out the zerk with a necro and go with a caster group. A while back they added these AAs called synergy focus AAs, when a toon casts a certain spell, it gives a buff to the entire group for a short duration. Typically, casters buff casters and melee buff melee so that's kind of the reason to go with picking a melee group vs a caster group.
So yea, I'd swap the cleric out for either a bard if you wanna go for a melee comp or a chanter if you want to go for more of a caster comp. Other than that, SK/SHM is great and you just gotta pick your poison on the kind of DPS you wanna do.
Now, as far as the plugins and stuff go, the CWTN plugins are AWESOME. Very easy to get working and very well performing. That being said, they're $20 a class (per year), so if that's out of your price range, that's totally ok. There are a ton of other options now! If you're just starting out and don't really have any programming experience or anything like that, I'd recommend RGMercs. Basically, it's a macro set up to just be plug and play. You just target your assist and type /rgstart and it just works. Once you're more comfortable/familiar, KA is still kind of the go to I think. KA (KissAssist) is WAY more customizable than RGMercs, and that customization is done through ini files. There are a LOT of ini files available on the site that should give you a nice jumping off point and you can further customize from there. From what I understand, there are a few other options including AKA (AlsoKissAssist), Xgen and probably others but if I'm 100% honest, I haven't messed with them yet.
Anyway! Welcome back! I hope you have a great time and I highly recommend you join the RG discord too. If you ever have a question a ton of the guys who actually know what they're talking about (way more than I do) are always in there and are super nice and always willing to help.
TL;DR
1. Group comp is off meta and missing a CC class for the typical TANK/HEAL/CC/3DPS set up, the meta now is either a melee or caster group
2. Plugins are great but cost money, there are other options though
3. If you still have questions, join the discord! There's a ton of really helpful people on there.