I am on EAD. I get offers to work on 1099 with more hourly rate.
you get more on 1099 because you need to pay double social security and medicare
1. Will that cause any problem for GC?
h1b people are not allowed to work on 1099. you wont have any problem if you use your ead for a fulltime job with w2 and then any number of 1099 part time jobs.
if the job offered is the only one then it will be a serious issue later. you do the math and ask them pay your wage as w2
2. What if I get RFE and USCIS asks for paystubs?
see above
3. After taxes are paid, is there a big difference in 1099 and W2? Recruiters are paying me more on 1099.
1099 is purely a temporary and w2 is "generally" permanent position. you need show permanent job offer for green card. main difference between 1099 & w2 is that in w2 employer will withhold your tax (federal, ss, medicare) and he also matches your ss + medicare. whereas in 1099 they just give you the full amount and you are responsible for paying federal, double ss, double medicare. also people who get 1099 are generally termed as self-employed which is contradictory to h1 or greencard.
