What are the most essential skills you would need in the Hardware Engineering field?

I would suggest a few things which are important for any field of work and is just not limited to Hardware Engineering.

1. Logical Approach / Reasoning - This is very important aspect of any job, if you can think logically and have a good logical reasoning there is a very high chance of success.
2. Analytical Thinking - Just like a logical approach is important to understand anything so is analytical thinking to put things step by step and make a framework out of it.
3. Ask Questions - When in doubt ask the question, asking question does not display weakness instead its a strength, I always prefer to ask a question and clear my doubts rather than not asking it and stay fool forever.
4. Softskills - Last but not the least yes softskills are very important in any line of business, no one likes to talk to a rude or a disrespectful person. We like to be treated nicely and hence we should treat others the way we would like to get treated. This level of basic courtesy is step one in terms of Softskills and the most important aspect too as its foundation of building as well as maintaining a relationship whether professional or personal.

I hope I answered the questions you had.

The soft skills which are required in every field is good spoken english, courtesy and able to handle pressure if you are pursuing a career in the private sector.

When you mention hardware engineer, what specific role or responsibility, do you have in your mind as there are different position names which are being used in the industry depending upon their role and responsibility so that , my answer would be of more informative for you