I've yet to see you post anything that's transformative about Dallas and Parker. The guys we see when they die were always those guys.
In this scene you've quoted:
Quote" It happens because that's what the Company wants to happen"
" Standard procedure is to do what the hell they tell you to do"- Dallas
Dallas also orders Ripley to take off despite her telling him the repairs weren't finished. Doesn't exactly scream 'Company drone'. He wants to do his job with the least amount of fuss and get paid at the end of it.
Quote
No, it's not. That's a false equivalency, Dallas didn't change by revealing his true motivations same for Parker.
More is revealed to the audience about Burke, Dallas and Parker throughout the story - but they don't change.
QuoteI stated she was by the book. She doesn't always follow orders see: letting Kane in after Dallas ORDERS her too.
As clearly stated in the film, Ripley was senior officer and legally obliged to have them wait for 24 hours for decontamination. Dallas tries to get her to break the law, and Ash outright does it.
Ripley doesn't challenge authority; she appeals to a higher authority ie. laws and Company rules, when her superiors aren't following them. Taking ones chances with three crew in a shuttle built for two in deep space, is not following the rules. By this point however, the higher authority doesn't care if she lives or dies, so she throws out the rule book.