With covid19 continues to spread, this might affect the universities in the next semesters as the number of students might drop and many universities are offering cheap online degrees compared with the expensive traditional degrees. Who can lose a job due to covid19 in academia? Instructors with annual contracts, postdocs, adjunct-faculty, pre-tenure faculty, tenure faculty, or even all and many could universities shut down.
Of all the examples you name, I think only those on annual contracts have much of any risk and I think that is small. The world isn't actually ending. Universities still have their mission(s): Teaching, Research, Service. That won't change unless the disruptions are much worse than are now foreseen or even likely.
Course delivery is being affected, but hasn't ended. Research goes on, though interrupted/slowed in some fields for safety. Funding for research is still in place and will probably continue. It will be a boon for some (biomedical) research.
Some marginal colleges will be in trouble. Think Walden University from the Doonesbury comic, but they were in trouble before this began. Tenure Track professors are unlikely to be affected because they represent the future of the university, not some disposable resource. Postdocs have contracts and funding in place for the most part, often by grants.
There is even a chance that the current disruption will increase the need for faculty in the short term.
But for long term effects we need to see how the hundreds to thousands of variables now in play work out over time. And it will take time since universities have quite a bit of built-in inertia. Whether "cheap online degrees" have any actual value is something yet to be determined. And they may not be as cheap as you think. Some online programs are extremely expensive to create. And the issue of the actual qualifications of those who take them is important and, perhaps, doubtful.
But even if a university were to try to deliver such a "cheap" degree there is the question of still needing to do research and that requires highly qualified personnel. There isn't a "cheap online research path" that has and likelihood of success.
Diploma mills have a poor history, being more associated with exploitation than with excellence.
Relax. Stay healthy. Do a good job. Climate change is a bigger risk than what we are going through in the current months.
Some people normally employed by colleges are at risk, of course. The people who clean the dormitories and prepare meals for resident students, for example. Lots of service jobs are at risk. Likewise, there are lots of small businesses in college towns that are at risk of failure, leaving their employees (including students) without resources.
Anybody might, anybody might not. Job contract duration and institutional/regional/disciplinary factors are more important than job title.
There are some institutions which are doomed over the long term to close, merge, or transform themselves because of demographic changes. Some of those institutions will be closing much sooner than was previously expected.
People with short-term and at-will contracts will loose their jobs first, just like every other industry.