Is there an inyan to say tehilim or give tzedaka or do mitzvos liluyi nishmas a nefel (who was given a name and buried) or is it considered in the Torah as if he doesn’t have a nefesh since it was born dead and didn’t live for 30 days.
Whether he has a nefesh or not I don’t know, but the halacha is that there is no kaddish said for him, and there is no need to do tikunim for the babies neshoma. The reason is because the nefel doesn’t have any din on him etc.
ON the other hand R’ Moshe Feinstein zt”l ( see igros Moshe Y:D 3-138), brings the gemora (Sanhedrin 110b, and Rashi D:H Msha’ah shnizra) that the neshoma of a stillborn baby has a chelek in olam haba, since he has already entered a human body. Not only that but it is totally clean of sin. In addition R’ Moshe writes that although all bodies buried outside of Eretz Yisroel will have to endure the pain called gilgul mechilos- the process of their bodies rolling to get to Eretz Yisroel, however these small babies will not have any pain because they don’t have any aveiros!
Additionally the Shulchan Aruch Y:D 263-5 says that the reason why a nefel is given a bris is because it has a chelek in olam haba and techiyas hameisim.
Therefore there is no need to do anything for them as a tikun neshoma, but they do have a chelek in olam haba, which the parents caused.
May HKB”H help that you should have many more healthy children
Y:D 344-4, Gesher Hachayim pg.119, Shut Chasam Sofer O:CH 144.