I'm not aware of Tolkien creating rules for Elvish succession, and I doubt he ever discussed it in detail. The main reason is that Elves, under normal circumstances, do not die. Therefore, succession is not even supposed to be an issue. After the Noldor rebelled, left Valinor, and formed kingdoms in Middle Earth in opposition to Morgoth, then the deaths of kings in battle did require that leadership be passed on. But, from an Elven point of view, all "succession" is emergency succession. If your father is the king, if everything goes well, you will never become king. And unless you hate your father, you prefer it that way. Legolas is a prince, but he never shows any sign of expecting to becomg king one day. Elves simply don't think like that.
Most of the individual instances where female Elves did not succeed male relatives to the High Kingship included extenuating circumstances. Yes, Findis was passed over for rule, but she remained in Valinor after the rebellion of the Noldor, so she could not have succeeded Finwe as their leader. And as you said, Irime's fate is unknown. Succession to the High Kingship is so rare that it would be difficult to draw a general principle from these incidents alone. I think that, if the Elves were to draw up laws of succession (which they do not seem to have done), a form of Salic law would be likely, given how few female leaders are among the Elves.
Still, there are other possibilities. Succession is, after all, only necessary because Middle Earth is in a state of war. (Even leadership is necessary, in part, because of the war--had the Noldor remained in Valinor, there would have been no High Kings.) Given the very physical nature of combat at that time, most female Elves would not have been successful warriors--a problem which would lead many Elves to prefer male leaders. Females who could provide protection--Melian, for instance, and later Galadriel--were a different story. Galadriel ultimately becomes, with her husband Celeborn, joint-ruler of Lothlorien--which passed into their hands after the death of Amroth. Amroth was a Sindarin Elf and had no direct relationship to either one. Celeborn was at least Sindarin. Yet Galadriel became a ruler of Lothlorien as well, when she was one of the Noldor. Fewer Elven women become leaders than Elven men, but the Elves seem to have no difficulty accepting Galadriel's leadership. They recognize the protection her wisdom offers them and value it.
In sum: succession to the High Kingship happens only a few times throughout Elvish history, so it is difficult to determine a set of rules that govern it. Succession rules among the Elves in general seem to vary. Some Elven leaders succeed others because they are male relatives. Some are male relatives who happen to be close by when disaster strikes. Some are chosen simply for their wisdom. It depends on who is being succeeded, who is doing the choosing, what the political situation is, and what candidates are available. In all cases succession is considered unfortunate.
