Heard of HAJ and NUE. Source is a reliable user of an German forum. Announcement should be in a few weeks.
Slots for 3 routes - does it mean 3 routes with each double daily (or more) or 3 routes with just one daily flight?
Right now there aren't any flights TXL-STN. TXL-LGW would be a new route and in competion to EZY LGW-SXF.