I have identified a solution that works :)
When exporting the env variable, hit the enter key on the command line and keep adding lines and then close the quotes on the least line. This would look like the following:
prompt:> export mycs='element /reuse /main/LATEST
> element /reuse/ip /main/LATEST
> element /reuse/ip/file.txt /main/LATEST'
Then, test it out using echo with double quotes around the variable as:
echo "$mycs"
Once formatted as wanted, simply pass in the variable to the Jenkins CLI to be used on the other side like this: