Any you wont be restricted at 350mb they both can handle that.
Yes.Thanks. I assume that one is a 1G and the other is 2.5G?
Yes.
I would use the 1Gb one as its Intel, unless your rooter supports 2.5Gb.
I should be ok. I have Orbi 353 router that has 3gb port.
Pretty sure the Orbi RBK353 are only 1gb ports.