Hi Julian,
1) No need to remove batteries, just power it on before plugging in the USB. It can be plugged and unplugged at any time without affecting normal operation or playing, unless it is a PC which may cause HW reset (I guess this depends on OS and drivers).
2) Looks like your console is set to use RTS/CTS flow control? In Gecho the RTS line is used for HW reset, it is useful when flashing the firmware. Try to disable that in the settings - for example in PuTTY it's the "None (DTR/RTS disable)" option.
3) These settings look good (assuming it is no parity, 8 data bits, 1 stop bit).
Cheers,
Mario