Will assume you have very specialised travel insurance. The cheap deals won't necessarily cover a pre-existing condition.

No idea about what LORAL SPACE & COMM rate means at the IC Yokohama.

For changing money. Would not advise changing more than the minimum at VIE. You'll get a better exchange rate using an ATM at Narita. Seems you will be with Lufthansa flying into Terminal 1. There is both a Citibank ATM as well as a 7-11 ATM around the Arrivals Hall. Airport Staff will be there and willing to assist you if you cannot find them. Please bear in mind that the ATMs from other companies may be useless.

You might find it lessens stress to have at least 5,000yen when you arrive. This will be more than enough to get you to the hotel with public transport. Once you are at the hotel the concierge will be able to give you further assistance.

When you go out and about, rather than asking for help directly, keep a map with you and look at it in a puzzled manner (your hotel will be able to provide you with these). I understand that you might not be able to see the map well but it will be a signal to others that you need some help. Don't try and pick out the 5% of people who might feel comfortable enough speaking English with you, let them come to you. That map and you looking lost is like a distress beacon. There are a lot of very, VERY kind people in Japan. Enjoy your visit. Don't worry.