The J-1 does indeed require one to remain outside the US (except for tourist type visits) for at least 1 year (may be upto 2, but not sure)...but within that time, many non-US students who have studeid and worked hard can have built some flight time to kick-start their careers in their home country. It is somuch easier to obtain (through an approved school) than an H1-B.
I looked at the H1-B and for those that have a Degree and probably some associated work-history in that field AND can find a US sponsor (not so easy)...i'd say go for it..as it gives upto 3 yrs work privilage with an extension upto 3 yrs i believe. BUT this assumes a lot of ducks line up and that the student is appropriately qualified. Good luck if this is you.
Regarding flight pay...varies alot from around $10
pr hour to $25 or $30 per hour. Note almost all flight schools pay on the basis of billable work done (flight hobbs meters, pre/post briefings and logged ground school)....Many seem to fall into the $15-$18 epr hour range...depending on how busy the school can keep you. It is possible to make $20,000 to $30,000 per year as a CFI...In Los Angeles, I was on $22/hr rising to $27 and made just over $30k in my first year...but that (helicopter) school paid better than average....factor in to the cost of living in the area, not just the bottom line $$$
There really are jobs out there for new CFI's if you are willing to re-locate and be flexible and show you are keen. Some CFI's i've come across just dont want to move out of their local area and wonder why employers are not batering their doors down with offers. Apply to any and all schools you are interested in...dont wait to see if they put an advert online for a job...many dont!
best of continued luck.