The tour includes entry but does not include the fee for the special bus. You have to pay for the special bus there is no way round this, but because the price is subject to change it is not included in the price of the tour

I am not the tour provider.

Yes. Every day seasonally. Check the website

Check Viator on google

It depends on how much you want to explore when you get to Obersalzberg. You are going to be on a bus for 1/2 the day. Back and forth from Munich, then up and down to Kehlsteinhaus. When you're up at Kehlsteinhaus, there is a lot of exploring you can do further up the mountain peak, down below you can walk to the Document Center, into the Bunkers, over to the remains of the Berghof, etc. So, if your little one is up for exploring that day - you'll definitely get more out of it. I don't recall seeing anyone with strollers - the fold-up umbrella style would be your best bet.

The trip up to Obersalzberg is pretty much a straight shot from downtown Munich on Friday it took a little over 2 hours. On the way back, we took a leisurely ride back through Berchtesgaden, with a brief photo stop which made it a little over 3 hours. The bus driver had plenty of drinks (water, beer and soda) for nominal prices and there was a WC on the bus.

From the bus station to the base of the mountain was around two hours. We were there for a number of hours touring the Eagle’s Nest and having lunch before heading back. All in, it was a ~9 hour day.