@ VivisectedEngineer
It's not a theory, it's just a logical conclusion with the information presented in the 4 main Alien movies that are basically as canon as it gets. The man we know as Michael Bishop in Alien3 was never formally introduced. Luckily Ingeniero has the facts on who Michael Bishop is; otherwise all we could do is draw logical conclusions.
The clip you mention about Bishop being impaled by the Xeno Queen is a random incident and I don't think is enough evidence to assert that androids can feel pain. I'm not saying they do or they don't, but if they do feel pain, then they are able to ignore it, unlike humans. This is factual when you consider Ash being "brought back from the dead" with only his head in Alien. This is also fact with Bishop being "brought back from the dead" in Alien3. This is also a fact with David becoming headless in Prometheus. This is also the case with Call in Alien: Resurrection who was shot. In all of those situations, neither android expressed pain, or at least much, even though they were in pieces or were shot. There voices might have been messed up in some of those examples, but I guess that could be expected when all that's left of an android is its' head and I wouldn't be surprised if an android that lost its' head also experienced some messed up interior components which would mess with the androids voice. There is also fact in Alien: Covenant where Walter gets his hand eaten by acid when he punched the Neomorph. I don't remember Walter ever experiencing pain. I just remember him with look of fear or surprise or determination on his face (I can't actual remember that part very well, but I'm pretty sure he didn't show signs of pain.)
For Michael Bishop to have enough adrenaline running through him to ignore a massive gash in the back of his head with his ear falling off wouldn't make sense to me. I do agree that humans can receive extra adrenaline in moments of life or death or situations similar, but Michael Bishop doesn't seem to fit the bill for that to happen for me. To me, Michael Bishop is trying to have a conversation that he so desperately wants to go his way. That blow would have easily knocked out a normal human being and would likely result in a concussion or even cause death. Plus, I don't think he wants a Xeno Queen more than what his life is worth. That's the question with all WY employees, "Would they sacrifice themselves for a chance to have a Xeno?" I think we have our answer, in a way, in Alien: Resurrection, which is, "No." It's not WY employees in A:R, but they are humans that want something from the Xeno and are willing to steal people to get it. They even have the technology to remove the Xeno from themselves, but they still choose to steal people to get impregnated with the Xeno.
On your third point, I thought that the Bishop that's trying to get Ripley from killing herself is an android with a human brain in it, which is why he bleeds red, but according to the facts from Ingeniero, it's Michael Bishop with human technological upgrades. That makes sense to me and is the only example that I know of in the Alien-verse where humans have merged with technology.
Of course, all of my ideas on androids come from me not thinking that they have many, if any, actual human emotions. Androids could be programmed to act like they are experiencing pain because, as David said in Prometheus to the question, "Why do you wear a space suit?" David replies, "Because it makes your kind (humans) feel more comfortable if the android blends in with humans." (or something like that). So, that pain you think Bishop is feeling in the movie Aliens could all be part of his programming, but he may not actually be feeling anything. That brings the question, "If I think, do I feel?" This is a very abstract question and I'm sure different people have different beliefs on how this relates to AI androids. AI stands for Artificial Intelligience. Here is one definition for it...
ar·ti·fi·cial in·tel·li·gence
the theory and development of computer systems able to perform tasks that normally require human intelligence, such as visual perception, speech recognition, decision-making, and translation between languages.
It doesn't state feelings in there, but if androids had AI and feelings, I'm sure they could make better and more human decisions. We discussed emotions with androids early and I really don't feel like continuing that debate. I feel like we kind of have our own, yet separate beliefs on that.