1) Can an organ of a dead Jew be given to another Jew for the purpose of saving his life?
2) If a Jew has a relative that is buried overseas, and nobody ever visits the kever, can the body be brought to Israel where the relatives of the deceased will visit the kever and daven at the kever thereby giving kavod to the deceased? (In these circumstances what is the halacha in respect of kavod hameis)
3) Over 20 years ago I named one of my children Rivka after a great grandmother, who was known to be an aishes chayil. I have since found out that my great grandmother had 2 names Rivka Nechi, Is there a way that we can add this second name to my daughters name?
1) Yes. For the purpose of saving a life, there is no question that organs can be donated. However, the problem in organ donating is that one must be sure that the donor is halachically dead. This is not a simple matter, and we have discussed it briefly here: https://dinonline.org/2011/01/09/organ-donation/.
2) Although in general, it is forbidden to move a meis from one location to another, it is permitted to relocate a grave in Israel, for this serves to atone for the meis (see Shulchan Aruch, Yoreh De’ah 363:1; Tur; Perishah 6; Shach 3).
3) It is not recommended to change a name, without there being a grave reason for doing so. In addition, it is unlikely that your daughter will be actually called by the name Nechi, which would render the change insignificant — a name is only a name if it is used. If the main name that was used by your great-grandmother was Rivka, then your daughter is called after her with the single name, and according to some poskim one out of two names is also significant. See our article concerning this issue, here: https://dinonline.org/2010/12/23/shemos-his-name-in-israel-shall-be/.