Thanks for the kind words first of all!
Yes, I had no qualms at all about travelling in Western Ukraine and even in Odessa and in fact I was proven right - there was really no signs of any kind of conflict in Lviv whatsoever. The only reminders were a few billboards calling to help the troops, a few stands in a park about that and a display of a destroyed car with bullets and a lot of Ukrainian flags gathering support for the war effort. Otherwise, there is zero problems and you could probably fool yourself into thinking there is nothing going on in the east.
I don't think German would be of any use in Ukraine honestly - you're better of trying anything in English. Russian is also widely spoken and very useful, so I would perhaps recommend trying to learn a few things in Russian at least. Otherwise, English is your best bet. If you're in Lviv, most places downtown will probably be able to help you in English - bars, restaurants etc. Train station - not so much. So learning a few basic things would probably be useful, although I'm sure you can get around without it.
Buying tickets online is in ENGLISH
The website is this:
http://booking.uz.gov.ua/en/and you need to create an account but it seems rather painless. Also, if at first try you book and it rejects your card, worry not - try again. It seems to do that every now and again. Some of the tickets are online and spit out a pdf with a boarding pass and some you actually have to take to a ticket agent and ask to print - the word for that would be друк and it's pronounced "d-r-oo-k"
If you have any other questions, do not hesitate to ask