J1/J2 visa

Hi to all, if wife has J1 visa and husband has a J2 visa , who should file form 8843 for child and if both have W-2 should file each as non-resident 1040-NR separately?

 J1 visa should file 8843 for herself and husband as well or J2 visa can file 8843 by himself since has a W-2 and J1 file 8843 for herself. 

I was wondering if husband has other income like online shop as self-employed (beside W-2 ) where should enter on 1040-NR?

should file Sch C but no pay SE tax also? If so, what part of Sc C indicates to exempt of SE for a non-resident. no treaty tax included on visa.

Please help.