You seem to be giving yourself an aweful lot of work. Is there anything you actually need that can't be met by any of the physics engines you named?
I started this thread out of a mistaken name so as for the physics engines, i will have to really test them out.
None of them is perfect, i read a detailed comparison of them including newton and they all had their ups and downs.
UNREAL ENGINE 4:
Total LOC: ~3M Lines
Total Languages: ~32
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GREAT QUOTES:
I can do ALL things through Christ - Jesus Christ
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Logic will get you from A-Z, imagination gets you everywhere - Albert Einstein
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The problems of the world cannot be solved by skeptics or cynics whose horizons are limited by the obvious realities. - John F. Kennedy
When you crack absolutely perfect mechanics simulation with passable performance, do be sure to let the rest of us know how. 
