Is adopting the Hanafi maddhab's fatwa regarding a small amount of impurity considered following the path of ease, or is it adopted because it is a valid opinion that some scholars and shaykhs have agreed with?

An ordinary Muslim (layperson) is not obligated to adhere to a specific madhhab (school of thought) in matters of disagreement. Rather, it is permissible for him to adopt a view considered valid by scholars. It is permissible to follow any of the four Imams or others whose madhhab has been preserved and documented. Therefore, you may adopt the Hanafi madhhab in the aforementioned issue as long as you believe you are following a recognized madhhab. This is not considered blameworthy pursuit of concessions unless one constantly adheres to it. However, for someone who adopts it out of necessity, there is no harm in it.