I pm'd u. But I'll help you here.
For both group and solo play Wizard is the strongest, and probably easiest class to play. Vyrs + Chantodos Archon is great for group and solo. Starpact is a difficult build to learn, but it's the main dps in GR group meta.
FG doesn't really work for D3 since there's no trading (except between those who were in the game while the item dropped... and the trade window expires 2 hours after drop).
But you can buy a 1-70 carry, rift and greater rift carries. A lot of people include items dropped in prices. It's best to buy carries from those specific to the class u choose so they can drop items for ur char.