It's brutal that Cinta died so ignominiously, but I do think they spent the entire arc setting up that the Gormans were going to screw up. They spent multiple episodes building up that the Ghorman Front lacked experience/tactical knowledge and that was after the first arc where we saw an entire rebel cell that fell apart due to infighting and incompetence. The failings of various rebel groups and the way the rebels develop through this season does seem to be a theme. You're not the first person I've seen pick up on the bury your gays trope, but I wonder if it's fair considering how many named characters have been killed in this show (and may still be).
Also, regarding your point about Bix and Cassia's mission. This is probably the most vulnerable that Gorst was ever going to be. Partagaz mentions that Naval Intelligence lobbied for Gorst, so presumably they knew about Gorst, which means that the circle of people that knew about him was much substantially larger than the ISB for the first time and therefore the circle of possible leaks is much larger.