Hi, Andrey!
2) I can't find RJ-45 gigabit module with industrial temperature range
(-40C..+75C). Either use 0-70C agree or help required.
I found one. Part number code: 7499111440A. It's available herehttp://export.farnell.com/wuerth-elektronik/7499111440a/connector-smd-rj-45/dp/1636393?Ntt=7499111440A . Datasheet included to this e-mail.
Regards, Andrew Karpenkov