Yeah, the stealth from Shroomite is really good, but... Really are you just standing still while fighting with a boss? In most cases(especially the Lunar Events) you might end up not using the stealth even one little second, so it's important to compare the non-stealth damage values. At this point Shroomite doesn't grant a good increase than Titanium, moreover you will lose the Shadow Dodge buff which is a good aid.
You said you farmed crates once, then I think you can do it again, so do it
Really, it's all worth it. May be, you might try to complete the whole hardmode by just using the Titanium Ranger, if someone could do this to the Golem on expert mode, then another one can finish the Moon Lord on normal mode, at least this is what I think.
About Vortex and Nebula Pillars, all Vortex mobs and projectiles CAN'T pass trough blocks, and all Nebula projectiles CAN pass through blocks, and Nebula mobs know that so the only option is flying non-stop and spamming chlorophyte bullets.
Vortex: Easily cheesable as Martians, Nebula: Don't even think to cheese these guys...