Sorry, but you are incorrect. This is a common misconception...but still wrong.
The climb gradient is based on normal operations, not EO operations. Just because you may be able to achieve that gradient EO is irrelevant to the regulatory environment.
The NET climb profile EO is much different that the NET climb profile all engine.
You are a declared emergency on EO. There is NO criteria that addresses EO parameters, therefor NEVER expect that the DA/MDA includes this emergency operation.
There are 'specials' that address EO operations, but unless you have one of those specific designs, you are NOT covered for EO.
Let's face it, if all the engines are running, this discussion is purely hypothetical. Any modern aircraft will kill any of the requirements (even a 402).
The criteria assumes all engines, and a worst case scenario with aircraft class, performance loading, and temperatures.
This criteria is used to evaluate obstacles to set the DA/MDA...obstacle determine the DA/MDA.