When He makes such negative assumptions, how do I firmly (but professionally) call it out? Besides calling it out, is there something else I can do to suppress this behavior in him?
Directly address the behavior as it happens. If he snickers in a meeting again, say "Why are you here if you're not going to take this meeting seriously?" Same with being dismissive or other disruptive behavior. Call it out immediately and make him explain his behavior.
How can I stay true to my values and not give in (If I take more time, He might report to the higher-ups that I am not as committed to a quick solution as He is)?
Make sure your doing Continuous Integration so you can show the executives that each change goes through a battery of test and once it passes is available on a development server. This process should be automated, so executives can see an automatic quick turnaround.
Once you have CI/CD in place, as a team (including the new team member), need to decide on coding and test coverage standards, and the entire time needs to enforce it. Let the new team member advocate for quick turnaround, and you can advocate for higher test coverage and more code standards. He'll likely be more receptive since he gets a say in the process.
Are there solutions (to deal with this guy) that I am not thinking of?
It sounds like he likes to make snide comments about people's work. Calling out these comments and putting him on the spot may fix it. If it doesn't, you and any other team members who feel targeted need to speak with him as a group. Give specific examples of bad behavior, and say "This behavior needs to stop or we won't be able to work effectively with you as a team."
You can try freezing him out and making his work life miserable, but 1) it's also difficult on you to blatantly ignore people 2) he'll probably run to management.
I would start looking for a new job as it sounds like you'll likely get in management cross-hairs for this
If you have come across such characters, are there other issues I should expect?
Yes, I refused to work with him after he lied to me. I made sure everyone knew about it and got transferred.. I was also prepared to quit if I had to continue working with him.