I think you forgot to add the link: Here’s a no-paywall version.

That depends on what level you want to achieve. Some plasma blob with a membrane around it that is able to just replicate in a perfectly controlled and balanced nutrient solution is one thing is probably not easy, but the lowest level that needs to be achieved to claim this term.

If you want something that you can drop into a petri dish with some agar-agar and real, competing bacteria, and be able to survive and thrive, well, that is a completely different level.