Is there a rule of thumb avg. kw/hr usage for a 3.5 ton unit?  1st stage? 2nd stage? 

Most heat pumps use about 1 KWh per ton of heat pump capacity, + or - 20%.

Performance tables at manufacturer websites give exact numbers (actually, I think they are predictions - I don't think anyone gathered the tens of thousands of data points contained in those tables), but I'd expect them to be fairly accurate.

1 kw / nominal ton corresponds to a COP of 3.52 or EER of 12.

1st stage should be about 60% power of 2nd stage, more or less

My 5 ton Geocomfort has a rating of 2.37kw with a EWT of 30 when running in low capacity and 4.16kw in the high capacity, how does that relate to stage1
vs stage2 is "low capacity" and "high capacity" just another name for stage1 and stage2 ? I was told when my geo runs 100% it runs at half load, is that another name for "low capacity or stage1 ? sorry but im trying to understand the terminology.

low = stage 1; high = stage 2

Not sure about "I was told when my geo runs 100% it runs at half load" other than it may be a way of explaining very long run times. It actually runs at about 2/3 load in low stage, and long runs in low stage tend to be efficient, quiet, and comfortable - heat spreads more evenly throughout house.