Who are the poskim that dealt with the shailo l’maseh of a father-in-law and possible chosson having the same name (mamash the same name, for exactly “Shmuel Yehuda” and “Shmuel Yehuda”)
The idea of being particular for same names comes from Rabbi Yehudah Ha-Chassid.
Some are particular for this matter, and others are not particular. From personal experience, I can say that in general Rav Elyashiv shlita was not very particular about this, whereas his son-is-law, Rav Chaim Kanievsky, is very particular.
For sources, see: Noda Biyhuda Tinyana EH 77; Ezras Kohen 5:7; Divrei Chaim EH 8; Orchos Rabbeinu 4:pp. 246-7; see also Maaseh Ish 7:130-1.