ADF can only scan one-sided. However, "manual duplex" works: scan sheet1-pageA, turn sheet1 over, scan sheet1-pageB. E.g. into a PDF file (option: Multi-Page).

I have not been able to find out. I can only scan one page (several also possible with the automatic feeder - but only one-sided). It also only works on a USB stick. I could not install it directly on the PC. But I am basically very satisfied with the device.