can marry a boy beloging to kasyapa, dhanunjaya & koundinya gotras
Yes. Rajputs can be of Kashyap gotra. The lineage of Rajputras that were shishyas of Maharishi Kashyap would be Rajputs of Kashyap Gotra.
Marraiage with in same Gotra is not good / not permitted. Any other Gotra is ok.
Vasistha was one of the Rishi munis in Hindu religion. Gotra is a sanskrit word which somehow means family. So, someone who is descendant of Vashistha Rishi is said to have Vasistha gotra.
Yes Naga gotra is of Kshatriya caste.
sub gotra of singhal
Yes according to gotras as long as you are from different gotras you can marry each other. But also Caste System do matter in Hinduism.
Rajput/ Kshatriya & Brahmins both have similar Gotras as they actually belong to same origin, race, belief & school. Therefore they can equally be of vasishtha, bhardwaj, jamadagni, gautam, atri and agastya or Atri, Bhardwaj, Garg, Gautam, Kaushik, Shandilya & Shrivats Gotras. The gotras are basically schools run by saptarishis and their descendants.
Bisen Rajputs have "Vatsa" gotra.
gotra is the family tree where you came from. Kul is very similar to gotras in most cases both are used interchangeably.
(Shiva) gotra , and nandi surname is a kayastha (kshatriya) .
Rajput/ Kshatriya & Brahmins both have almost similar Gotras & "Bhardwaj" is also one of them which is shared mostly by Baghel, Bais & Sisodias.Main Gotras: Vashista, Bharadvaja, Jamadagni, Gautama, Atri, Visvamitra, and Agastya.Later on Most commonly referred as : Atri, Bhardwaj, Garg, Gautam, Kaushik, Shandilya & Shrivats Gotras.
Akshinthala Gotra (It may be came one of the Saptha Rushis Maha Rushi Vashishta)