These are usually the sorts of things I would ask during a phone or in-person interview. Your questions indicate that you've come from environments where pressure was high, or the business faced hard times - use those to explain your questions.
For example, for #2: "My current company has fallen upon some hard times recently (hence my job search). What are your projections for your market? It looks fairly solid / potentially weak to me as an outsider. How would a downturn in the market affect the company, or my role?" (My second job was at a company that provided software tools to realtors - right around the burst of the housing bubble. I asked a question very similar to this.)
#4: "Due to financial strain, my current company has had to lay off some workers and increase the workload for the rest of us. What is your company's position on work/life balance? I understand that late hours are occasionally necessary - have you found it to be more common at certain times of year, or around certain events?"
#1: "What sorts of tools do you use? Is there a process for getting new tools or additional training? How do you handle the customer acquisition process?"
As far as #3, I would expect them to be giving you the standard benefits spiel around the time of your interview anyway, so that you'd be able to factor that into your decision.
How can I collect more info?
You could look for contacts on LinkedIn and ask; you could look at their website; you could look for anonymous reviews on sites like GlassDoor.
What other things should I look for?
This one's usually different for everyone, but general things could include amount of out-of-office travel, travel distance between home and work, review & raise schedule, feedback processes, expected breakdown of time in a typical week (such as "you'll be in meetings 25 hours a week, on the phones another 12 hours, etc."), or other benefits-related questions you haven't had answered yet, like vacation/sick time, 401(k) participation, etc.