I can only talk about the 757 with RB211 535E4 engines. I have many thousands of hours on the type and have never seen the the EGT close to limits.
I say again, as far as I know there is no 757 procedure for a Bleeds Off take-off.
As for reducing thrust below 400', this would have performance implications .. the usual is 1000'agl or 1500'agl.