Quite welcome bud. I'm sorry I can't tell you much about those other players, i'm not familiar with any of them. I'll give you a team here that would be considered the most standard build for the type of GSCers you're talking about:
1.Raikou
Thunder, hp ice, rest, sleep talk
2. Cloyster
Spikes, toxic, surf, explosion
3. Snorlax
Lovely Kiss, curse/belly drum, return, rest
4. Suicune
Toxic/ice beam, surf, rest, sleep talk
5. Skarmory
Toxic/curse, drill peck, whirlwind, rest
6. Rhydon
Curse, earthquake, rock slide, roar
(perish trap misdreavus is actually more common here but since sleep perish trap & double team is banned I feel rhydon pulls its weight a lot more)
Leftovers on all pokes.
Without going into in depth analysis (it's probably already been done on this page) this is the classic defensive team, and really one of the most solid combos you can get in GSC. I would lean towards Toxic on the options there. If you plan on modding/customizing anything suicune and rhydon are the best ones to switch up, just be aware that suicune is important for checking mixed attackers, primarily Nidoking who will chew through this team without a sleep talking check. For example if you switch suicune for exeggutor you'll need to make snorlax a sleep talker for Nidoking. The #6 slot is a secondary check for snorlax with a fire move as it kills skarm so if you change him you need to implement a plan for firelaxs. I'm not sure what your gen 2 experience is but this team is good for beginners as its easy to use and absolutely holds its own in the high end of the tier too.