(a) On Insights to the Daf 103 you refer to Rebbi's neshama as still being in his body after his p'tirah. I always had the impression that after a tzaddik dies his neshama goes to his reward i.e. If a person was not a tzaddik his neshama goes through a purification process of some gehinnom for up to 12 months. If he is a tzaddik or after a year for non tzadikkim he gets his portion in olam haba. Everything in hashkafa and philosophy, in other gemoras and in the Rambam and others seems to indicate this. A person who was not a complete tzaddik may come back to the kever for up to a year as the body deteriorates. He feels some pain and sorrow in that bodily deterioration.
The idea that a tzaddik such as Rebbi still stays in his body rather than going up to Gan Eden seems to contradict this.
(b) Also it seems a little strange to me that a tzaddik or anyone should renounce all pleasure from this world. Why would Hash-m create all of these pleasures if not for us to enjoy them? Even moderately. This concept is even included in the b'racha we say when we see fruit trees budding in Nissan, that Hash-m created these things to give people pleasure.
(b) Rebbi did not derive pleasure ... My question is then why do we have to give an account of ourselves for permissible pleasure that was given to enjoy? Would it not have been meritorious to enjoy those things given to us to enjoy because they have been granted to us and that we should show that we appreciate the gifts?
(c) "Great are the Deeds of Chiya." He understood that complete holiness should prevail in everything we do. The Seforno brings this out in reference to the Mishkan noting that Zadikim (such as Betzalel) built it in complete holiness and for this reason our enemies were not able to take it away from us. My question is, did this apply to the Luchos as well? It appears to me that they were captured from us by the Phillistines? If this was so, could you please explain how this was possible?
(a) There are many parts of the Neshamah, such that part of it remains in the body of Tzadikim (as the Gemara says in Shabbos 152b). The part which remains attached to the body does not hinder the Neshamah from going up to Gan Eden.
(b) Rebbi did not renounce pleasure from this world. There was always on Rebbi's table Tznon, Chazeres, and Kishus (which were appetite enhancers, see Tosfos in Avodah Zarah 11a). However, his level was such that although he did not deprive himself he did not actually enjoy the pleasures of this world, rather all his pleasure was from Torah and Mitzvos.
The MESILAS YESHARIM (ch. 13, "Perishus") discusses this question at length. He shows from a number of statements of Chazal that it is Asur to refrain from the pleasures of this world, and after citing many sources for this, he concludes, "The true principle, though, is that it is fit for a person to remove himself from any pleasure that is not necessary for the person in this world, and any pleasure that is necessary for him for whatever reason it may be, then if he separates from it he is considered a sinner."
Regarding the creations in this world which give us pleasure, the RAMBAM (Shemonah Perakim, Perek 5) writes that their purpose is to give Simchah (as a spiritual experience), and not necessarily to give physical pleasure.
(c) Even though the Luchos fell into the hands of the Plishtim, the Plishtim never had full dominion over them, and they were eventually returned, as we find in Nach, and they are still in existence today, in their place (wherever that might be).