Visitors Visa for sister and or Parents

[India2Pa]

Me and my husband are on H1B visa. both working. am currently pregnant and willing to sponsor both my sister, brother and/or Parents .If visa approved i would like my sister/brother to visit me first as my parents have some health issue . during the due date my parents can visit for a short trip.

None of these four(Sister/brother and Parents) have govt job here. my sister has recetly complete M.sc . mum- house wife . dad- business . my brothers had applied for F1 visa three time in the past 2 years and all three rejected with a pink slip.

Also, i recently changed my employer. I 797 from Old employers is valid untill March2014 and the new I797 from my current employer is still pending with USCIS.
my husbands I797 is valid untill March 2015. we both are full time and earning well.

MY Elder sister/Brotherin law also lives in USA on a F1/F2 visa now on OPT till April.

Now here are my questions .

1. who should sponsor me or my Husband ??? If i have to sponsor should i be submitting Old i797 since my new i797 is still pending.

2. Can my sister/brother alone attend the visa interview or is it suggested they go all together sister/brother and parents for stamping ??? which case is more likely to get the stamping done.

3. What reason to state while applying for Vise for all of them ?? (can we say family get together as my whole family will be here)

Thanks in advance.

[immihelp]

1. It does not matter.
If you do, submit what you have.
2. It does not matter. Each applicant is looked at separately.
3. Tourism

You brother and sister are very less likely to get visas.