[Advaita-l] loss of right to perform vaidhika karma

[Rajaram Venkataramani]

I asked this question in another thread but went unheard - resending with
more clarity. Do the following categories of people forever lose their
right to perform vaidhika karma or they can return to the vedic fold
through prayaschitta karma?

1.   Dwijas (incl. Kshatriyas and Vaishyas) who have not gone through
upanayam for more than three generations
2.   Dwijas who have not gone through upanayanam at the right age
3.   Dwijas who live abroad
4.   Dwijas who eat foot not cooked by one's mother, wife or self
5.   Dwijas who eat meat not offered in a vedic sacrifice
6.   Dwijas who drink alcohol at parties (not the soma juice offered in
sacrifice)
7.   Dwijas who have affairs outside marriage
8.   Dwijas who marry in the same gotra
9.   Dwijas who have an anuloma marriage
10. Dwijas who commit mahapadaka, atipadaka and upapadaka - either
mentally, in words or in action

 For travelling abroad leaving Bharatha Bhumi, I heard that there is a
ritual to destroy the negative effect.