New contracts have 35 days/5 weeks of leave. As Leipzig is your home base you have to take care about you accommodation yourself.
Difficult to say how many days you will spend in Leipzig, 3-5 per month, maybe more maybe less.
Part time is in general available, but as we are still quite short with crews at the moment it might take a while until more people can go on part time.
7/7 or similar is not available at the moment and there are no talks about it.