I went back to my save where I was doing another run after "upgrading" myself via the dev room (NG+, without the "+" difficulty of course).

It seems the game is scripted in the second half to really want you to run to hit the sewer lantern before any others. Keep in mind I had the "dev key" on me for this run so I don't know how much that glitches the game seeing how it's not intended to be used in a "serious" run.

One of the things you can do with the dev key is open up Gilbert's house at the beginning and explore, opening up the doors and shortcuts and such. So I did that, played the game beating Cleric Beast and Gascoigne, and then entering the Deep Night. All was fine there. 

Instead of giving chase through poison sewers with the Winter Lantern I decided to take advantage of some "emergent gameplay" by doing the skip where you can leap over the stairs by the elevator shortcut to Oedon Tomb blocked off by boulders. This allowed me to get to the Central Yharnam lantern, with the opened-up home of Gilbert, and kill off the Winter Lantern early so I wouldn't have to deal with it the rest of the game.

First glitches to occur are ones that almost softlock the game, but not quite. If you touch the Central Yharnam lantern first it seems, the "Lantern Activated!" message does not go away and you cannot move your character at all. You can attack however. Luckily I was able to move my character by attacking enough times to go down the path to the next screen. The prompt went away and I came back.

The same thing happened when I went to activate the Great Bridge lantern. I was also able to attack to propel myself forward to the next screen and back to get rid of the screen prompt. I saved the sewer lantern for last.

Now the big problem... I am unable to proceed with Eileen's quest and go to Oedon Tomb. Neither the dev nor sewer key will open the gates back up. Was it intended that you have to open them up from where you first encounter and are locked in with the Winter Lantern? Because I didn't do that. I get prompts saying that it's locked by the sewer key without it equipped but when I do equip it (or the dev key) it still will not open. 

It's unfortunate that there are no parryable enemies by the gate. Then I could at least try the glitch/exploit where you clip through certain terrain when giving a visceral to an enemy near a wall, gate or other form of collision. Or, just, being able to use the key I have and open the gate like normal? Annoying but, I can move on. Is this going to receive any more patches/bug fixes anytime soon? Seems like this is on hold for the moment.