Hello Ben,
first: I can give an opinion, but if you ask to 10 persons you may get 11 answers and not two are similar...
Originally Posted by: bpitchkites 
Well... I do not like very much the MM plans, they have fundamental fails - in my opinion. But if you know these fails and they do not disturb your railroad fun, it's fine.
What are these fails ?
first, the tiny curves. R1, R2 - have you seen a 141 (282 in american) Steamer in such curves? A 28cm coach? You can see the middle rail besides the car...
second, the very short lanes in the stations. The hidden station is made for trains of 1,20m maximum. That's 4 coaches and an electric locomotive, or three coaches and a steamer. But double rail line, so it's not a branch line...
third, not on all layouts but here it's hard : the spiral on the right with just 10 cm of height between entry and exit, on 1,25 rounds - your locos will scrap the wood above.
Originally Posted by: bpitchkites 
1. This layout has 2 schattenbahnhofs; since I know very little about train operations I am wondering if I need to have the Central Station or would the Mobile station be sufficient? Especially for operating these switches; it has 9 turnouts. I see that the mobile station can handle the switches and more locomotives than I will ever have. I don't want to be cheap but also don't want to buy the Central station if it is really not need to run 2 or 3 trains (in near future).
It's clear, the MS2 is not made for switching, it's possible but ennoying. But... you do not want to have automatic effects ? So, why not use analogical commands for your switches? Your switch motors gain in fiability when used on AC - but decoders provide DC.
If you want to switch by digital, then you may think about the CS3 - or about other systems to command your switches that may be connected to the MS2 system.
As long as you make run 3 trains max., you will not need more power than what provides the MS2.
Originally Posted by: bpitchkites 
2. I have been debating whether to buy a starter set to get the Mobile station plus another train and I can use the track from the set as well. Or do I just buy everything separately? I know the starter sets are marketed as being a good deal, etc.
They are - if you like the train in the starter set. Once you buy a train that will never roll on your layout, the starter set is a bad deal for you.
Originally Posted by: bpitchkites 
3. For the referenced layout, do you think I will need a booster?
I do not think so. If you needed a booster, you could not use a MS2, since it's not made for feeding a booster.
But if you want to be sure, you may think about separating the electrical circuits as if you had a booster, but you connect all to the same - CS or MS. The day you see that you are at the limit, you will separate the connections and install a booster. Then, with a CS3 or other central.
Never forget: all you may read in forums can enlargen your horizon, may help you to see clear - but may add more fog to your thinkings, too. And finally, it will be only your layout, not mine nor of who may have answered. You need no excuse for not following other people's opinions.