Trying to find if there is any method when using Zremesher at a very low poly count, to keep edges / creases and any other detail without it smoothing out.
?
If you use the “keep groups” function in zremesher, it will assign more geometry along polygroup borders, and is generally better at hardsurface polyflow than it was previously. This may be helpful for simpler objects, if you assign different polygroups along the borders you’d like to remain crisp.
For more complex high rez objects, you can export the high frequency detail like crisp edges as a normal map, and apply it to whatever low poly geometry is necessary to hold the silhouette in an external app. This may be useful in some situations.
For complex mechanical objects with deliberate economical topology and complicated creasing, there is still no magic button, and no substitute for manual modeling from low poly. Luckily Zbrush now has a better toolset in this regard than it did previously.
Thanks, will keep that in mind. 
Sure. Here’s a bit of information on using the new Keep Groups function in Zremesher 2.0 to define edges along polygroup borders:
http://docs.pixologic.com/user-guide/3d-modeling/topology/zremesher/hard-surfaces/
Also, I dont think I explained the second point very well. When remeshing an object you should consider crisp edges a fine detail, like skin pores or wrinkles. So in that case if you remesh a hard surface object and it ends up a bit mushy, you can reclaim that detail by subdividing the new mesh and Projecting the crisp edge detail from the original mesh to the new one. This moves you to a high poly workflow, and that detail must be recaptured in external programs with normal/displacement maps over a low poly silhouette. Or if your workflow allows it, you can just Decimate.
Low poly modeling with edge creasing is still the most reliable way to do hard surface and crisp edges, but it’s not always the easiest, and if you remesh you’re going to have to project detail to get it back in most cases. It just requires you to be familiar with all the approaches, and find what works best for your situation.
Not tried any projection methods yet, looking forward to trying it out.
Been practicing Zremesher guides with a various amount of sizes, especially smaller ones, which is actually doing a pretty good job with adaptive size & curves strength at 100.