Can we get library cards from other libraries to gain access to their ebooks?

It depends on the library and their rules. We have reciprocal agreements with Fort Vancouver Regional Library, Timberland Regional Library, and Kelso Public Library that allow Longview Library card holders to get free library cards from these libraries. However, they may have rules about electronic resources. For example, FVRL's website states that reciprocal cards can access everything except Hoopla (which we have anyway).

No you can't