@AeonSovarius This is actually a great opportunity for me, as I was starting to write a dredge primer for vintage. This will allow me to collect and summarize my thoughts, so hopefully I do a good job!
What is a regular dredge list: Right now, because of how the meta has evolved around beating PO, Pitch Dredge is really good.
Here is a sample list that I would recommend. I would say that it is less explosive than sum lists, but is still very explosive and powerful.
4 Hollow One may vs. SB really just depends on your list and available space/flex slots. Having HO main may make you a bit weaker G1, but will compensate by giving you more SB space for G2 and 3. Personally I dislike Gurmag Angler, and I think many people would agree. He is simply counter-intuitive to how dredge function at a basic level.
Bloodghast vs Ichorid: This is heavily dependent on your list. Fatestitcher dredge is much faster version that goes for the turn 1 or turn 2 kill as consistently and quickly as possible. This version achieves this by using either Sun Titan or Molderhulk to return a dredged Bazaar of Baghdad onto the battlefield to continue you dredging. As you could imagine, this makes Bloodghast pretty good. In most other lists though you want Ichorid, as he is the better and more synergistic threat. An example can be found
here
Lands: As with nearly all cards, this depends on your list. If you are running more Blooghast, you can run more consistent lands like Dakmor Salvage and Undiscovered Paradise. You do not have any other reason to not run the Rainbow land, as far as I know.
Creeping Chill: I personally really like the card, but it is completely unproven. I think if Oath or DPS where to become meta, then it could potential be good.
Elesh Norn and FKZ serve very different purposes (in my mind). FKZ, and Dragonlord Kolaghan (DLK), are both Dread Return (DR) targets that are meant to finish your opponent off the turn they are put onto the battle field. Elesh Norn, and occasionally Ashen Rider, serve more of a helping purpose. What I mean by that is they can take you from a not-winning position, into a very winning position (like if your opponent has a million creatures).
GY hate: I would say this has to do with the expected meta. I would avoid Ravenous Trap, as it seems very risky and bad in the mirror. For Leyline, it is generally seen as a low cost inclusion that can help you against a fair amount of the field because of how most decks abuse the graveyard.
Never ever run less than 4 Serum Powders. The only reason this deck is a thing is because of Bazaar. How do you maximize your chances of getting Bazaar? 4 Serum Powder. This deck is bad without Bazaar. Play 4 Serum Powder.
If you want to talk more or ask any more questions, just let me know. I am more than happy to answer anything. I hope this answers all your questions and that everything I wrote is clear. Good luck!