Life-cycle perspective and risks and opportunities

You need to conduct the assessment of the life-cycle stages of your and identify and evaluate environmental aspects in each stage. If you conducted the assessment of the environmental aspects in your processes, you covered the life-cycle stages that occur within your organization, so in addition you need to consider delivery to the customer, use and disposal of your product and identify environmental aspects, as well as the operational controls to be applied.

For more information, see: Lifecycle perspective in ISO 14001:2015 – What does it mean? https://advisera.com/14001academy/blog/2017/02/20/lifecycle-perspective-in-iso-140012015-what-does-it-mean/

2. Is there any difference in Risk & opportunities between ISO 9001 and ISO 14001 (apart from one is QA and other is Environmental !!)

There is no difference in requirements in terms of how the risks and opportunities will be identified and addressed, the only difference is in the scope as you already stated.

3. What is environmental design if my company is a building construction company and we are no responsibility to carry out the building design.

There is no such term as "environmental design" used in the standard, all you need to do is to identify and evaluate environmental aspects within your processes, and apply operational controls to the ones you determine as significant. If you don't have design and development process, it is impossible to apply and operational controls regarding the design.