Do I need to connect EFIS 2 Rx and Tx to the 696?
You should only connect the 696 or any other device to one of the screens, all the data is sent on the Ethernet to the other screen.
What data are you sending to the 696? We do not send any data to the 396, 496, or 696. You should not connect the EFIS TXD line to it.
I am planning on connecting the G430 serial 1 Tx to the 696 so that the 430 flight plan will show on the 696. Will doing this, along with EFIS 2 Tx to the 696, be OK?
No, on any serial line you can only have one TX, you can have multiple RX.