To your questions
1. The crimson mobs drop Crimson Veins which can be crafted into a Bloody Vein. Though they might not be spawning aswell anyway, this is being fixed in an upcoming update.
2. If you're playing on expert mode it drops nothing currently, this is being fixed inthe next update. IF you aren't, tell me and i'll check it out more.
3. Tesalite generation does not do well with other content mods.
1. Yeah, no veins were dropping at all.
2. I... See. That's an ... Interesting bug?
3. Ah. That should really be looked at. I've never seen a Terraria mod's ore generation interfere with another's.
Also some... Feedback and bugs I've noticed. I know, it's beta, but I still want to give my input in my experience with the mod.
The Heart of Cthulhu and Swarm Queen are... A tad underwhelming. Both appear to just hover above you and... Very,
very slowly spawn normal enemies of their respective biome. It may be that Leveled is messing some stuff up difficulty-wise, but I beat both incredibly easy and in under a minute. Flunky bosses are okay if done right but I think they could use some more work. Additionally, they should spawn unique versions of enemies, as most mods with flunky bosses do- which don't have their normal drop tables, because currently their spawns all seem to drop what the normal enemies of that variety would.
The Jungle Protector and Ocean Protector have kinda awkward sprites which don't really fit Terraria... In fact they look like they're a completely different resolution than Terraria's other sprites, though that may be an optical illusion due to their... Spherical nature. Not saying that sentient perfect shapes can't be oddly eldritch and menacing, but it really just doesn't look quite right. That said, I can pass that off as "it's beta" and I imagine they're at least semi-placeholder and not intended to be kept looking exactly the same. Even just some spinning with an afterimage and some particles would make them look less sportsball and more ... thingey?
The Expert Bags, when dropped as items, for some reason appear as 2x the intended size. Only occurs with this mod.
Also the Swarm Queen didn't drop any of its weapons. I believe it did drop an expert bag, but nothing of note came out of it.
The Ocean Protector, currently the final boss of the mod, has some excessively underwhelming mechanics and drops... I spawned it, and it literally just sat at the bottom of the Ocean. I thought the spawn had broken until I checked my minimap for it. I then flew down into the water and stood beside it. It did not move. I attacked it. It continued to not move. It nearly died. It finally started to move- and oh the fight was over.
It then proceeded to drop two new spears which is great for my melee character!... Except that both have fairly average stats which could easily fit... Pre-Golem, even, and are both too small, and far too identical aside from one being just objectively better than the other, with slightly longer reach and more damage at the same speed. They don't even have projectiles, they're just True Melee Spears, and not even very big ones. Considering that is supposed to be 3 bosses past the Moon Lord, they're very,
very in need of some better stats and/or unique gimmicks that make them stand out. Also they were both unmodified, dropped from the same boss, yet had different rarities. One was red and the other was purple. Which is kinda odd, since boss drops are usually raritied based on the same tier unless expert or really rare. Maybe one was supposed to be an expert drop? If so, it wasn't rainbowing correctly.
Sorry for being so harsh, but I think the idea of the mod is greatly promising but that in its current state, even bug-free, it isn't nearly as cohesive as it should be. Again, yes, I know it's in Beta, but I believe a priority shift is in order. I've noticed lots of weapons, armors, etc. which are sidegrades or minor upgrades to vanilla content, or (as in the cases of those spears) more like filler content. Go quality over quantity first and foremost, try coming up with unique ideas for each boss, and as many items as you can. Having some filler stuff is fine, but mods like Tremor are notorious for a reason; they focused too much on adding bulk of content, and not in making that content unique and worthwhile (and bugtested and balanced) and I don't want to see that repeated here; this mod has been on my radar for a long time and I see a lot of potential, but the current progress seems to be unfocused, which is never a good sign.
...Anyway, now that the Wall of Text has awoken, and fallen back asleep due to the sheer length of this technically-an-essay, just one more thing...
Please, please try to stay semi-active on the forums, even if it's just checking in once every few days, and occasionally copypasting the changelogs from the discord to the main post. I'm sure I can speak for a lot of people when I say that the trend of mods only having the bulk of their information on a Discord server or somesuch is incredibly annoying. Discord is great and all, but this really is the go-to place for Terraria mods, and the place most people will check first. Also not everyone has a Discord or wants to clutter it up with 23 individual mod servers.