Thanks. I fulfilled my requirements mostly with Sonoff Dual which costs around $10.
Open & close schedules are working. Network also. With the Sonoff Dual R2 and ESPurna Firmware one could add two more sensors. I will have to use that in the future to realize incoming and outgoing mower automatically.
My current setup – for the folks interested – may be seen here: https://skyynet.de/mowgli