Hrm. My commentary on cutting the fat from that list. I'd rather get some fairly comprehensive answers than a bunch of "We'll see"s on speculative information.
Your mapping process
The most common thing that people want to know about is your development process. If that’s something you can share, we would like to understand exactly what happens when you are designing a map from the ground up.
How many people are usually working on 1 map?
How closely do you work w/ the people doing textures and models?
What means does Valve utilize to test maps for balance?
How do you stay focused on your current projects? (Uh... they're professionals. Remove this one)
Could you describe for us what your alphas and betas look like? (Emphasize this. Very important + informative. I.E. say "Can we see developer-level paintovers of more of your maps, a la the beta Hydro + paintover present in one of your powerpoints?")
How do you approach a new layout or game type? And what do you use for inspiration when creating them? (Possibly remove. Wayyy too general. They use the cabal process anyway)
How do you create your textures? What program do you mainly use for TF2 artwork, and specifically textures? (Combine with the texture artist question above)
Is it possible to simplify Valve's map development process into bullet-points? (Emphasize this. It overlaps with some of the previous supernumerary questions, but it's better and more succinct in the answer it demands)
What compile settings do you use for your maps? (Possibly remove. HDR -final is what they use for their last builds.)
Do you ever work on more than 1 at a time? (Remove. Obviously they do multiple maps at once for several projects)
When do you determine a map is finished? Unlike the rest of us, Valve is able to update maps if an issue occurs. How helpful is this when deciding if a project is done or not? (Don't forget- their corporate name is VALVe not Valve)
How do you decide where to end the map borders in favor of a 3d skybox? (Possibly remove-generally, the more experienced community mappers would be able to answer this.)
General Inquiries
What is your favorite and/or least favorite part of creating a map? (Remove, opinion, not necessary?)
Do you have a favorite game type that you enjoy mapping for or playing? (Same- opinion?)
Do you ever try and sneak in easter eggs into your map? (Will this aid us in mapping?)
The new maps seem to be lacking in spytech. Where did it go? (Jackass thing to ask. Basically, "You're not doing your job right.")
Which of the current maps was most challenging to develop?
What kind of alternatives were considered to the Alpine environment?
Is it common for level design ideas and layouts to get traded in between different game development teams during the design process? IE: A design idea that turned out not to work so well for Episode 2 having made it's way into Team Fortress or Portal.
Any plans on expanding Ravine and/or Lumberyard into Full-sized maps? (Remove, this is a mapping interview, not a press conference. Speculation like this is boring and most likely unanswerable)
Since most displacements are natural cliffs, can you tell us how you created the satellite dish in Hydro?
What is your favorite entity and why?
What do you think is the coolest idea you've come up with while mapping, and did it end up in the final version?
Community Specific
Do you play any custom maps? (Remove, they've said they play custom maps. Replace with: "What would you do to change/fix the most popular community maps currently out there?)
What would you consider to be the most overlooked/underutilized stage of map development (ie. Concept, theme, layout, optimization, detailing, gameplay testing) by the community? (Remove. We know our own weaknesses, and these vary greatly mapper to mapper. Any answer would be an unhelpful generalization.)
You have shown that you are willing to also include maps with more experimental gametypes like cp_steel in your community map pack. How far would you be willing to take this? Would you include a map with a new prefix and a new gametype if it looked great, played great and was optimized well? (Remove. This is basically asking "HOW DO WE GET PICKED TO BE INCLUDED." Save it for the steampowered forums :|)
Do you ever get influences from community maps? (Remove, not necessary and too full of hubris)
When a community map becomes officially distributed, how much freedom/communication does the author have about updating it? (Remove. This is most likely NDA material, since the mappers who have been included have not provided commentary on it. Seems rude to ask either way.)