In certain contexts, "Führer" is fine. Just avoid it for political contexts. As of why "tour leader" is not accepted, I guess it's because there is the word "Reiseleiter", which is closer. But you can still try to propose it as a possible answer here.
I did the same, I was right on the mark too, this can especially help with long words like "Hubschrauberlandeplatz"
So the translation is "Helipad"
Yes, exactly. Ein Ratgeber can be for every topic ever (health, gardening, finance investment...) while ein Reiseführer will only give you advice for your travels, like the best hotels, restaurants and sights in the area.