Both Sony A99 II and Sony A7R II have Full frame sized 42.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Another similarity between these two cameras is that both Sony A7R II and Sony A99 II sensors lack anti-alias (Low-Pass) filters. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the A99 II and A7R II sensor size comparison.
Sony A99 II and Sony A7R II have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture.
DxOMark Sensor Scores
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. It scores camera sensors for color depth (DXO Portrait), dynamic range (DXO Landscape) and low-light sensitivity (DXO Sports), and also gives them an overall score. Sony A99 II and Sony A7R II sensors have been tested by DxO and the results show that A7R II has a better overall score of 98, 6 points higher compared to A99 II's score of 92.
Sony A99 II
Sony A7R II