Can I use this in a school? (Is a school a non-commercial enterprise?)
Yes, as long as you purchase the “Home and Student” edition. As the school is a not for profit entity and not engaged in retail activities, then it can be designated as a non-commercial enterprise.

Can I copy this content and distribute to multiple devices? How many copies?
Only one copy is allowed to be installed according to the licence – one backup copy may be requested from Microsoft and this also may not be copied.

Can I convert this content into a different format?
No, no changes can be made

Can I share it with another school?
No, one licence, one copy for the specific computer/user.

Will I own this content if I stop subscribing? What is the publisher removes it from sale?
If you stop subscribing your rights to the software also stop. If you have subscribed with a licence then Microsoft will upgrade or renew content. If you have used the software on a trial basis then rights are limited to the trial period. Microsoft uses licences so removing a product from sale can be covered by upgrading a licence or issuing a new one.

Content cannot be previewed though a user can purchase a trial version and choose not to continue with a subscription at the end of a trial.

Microsoft Software Licence Agreement. (n.d.). Microsoft office 2013 desktop application software. Retrieved from https://interact2.csu.edu.au/bbcswebdav/pid-2636381-dt-content-rid-4861340_1/courses/S-ETL503_201930_W_D/S-ETL503_201930_W_D_ImportedContent_20190109053749/PDF%20Files/Word_2013_English_73cd4bd0-863a-42d4-8da1-7ed333aaa640.pdf