3. You can use highly enriched uranium (HEU) for things other than weapons, but the weapons are the only things that require HEU. Medical isotopes and propulsion can be done with LEU. For instance, Argentina produces medical Mo99 from LEU [1]. US Navy wants to switch to LEU for submarines [2]. One of the reasons for these developments is exactly proliferation risk management.
[1] https://inis.iaea.org/records/fe51q-17w28/files/35015774.pdf
[2] https://fissilematerials.org/library/doe16.pdf