These trials and the validation can take about a year.
Here is the official list of currently being developed covid19 vaccines (all in pre-clinical stage)
https://www.who.int/blueprint/priority-diseases/key-action/n...
In the article I referenced, the company says they use a novel plant based method which allows mass production, and expect phase three clinical trials to be completed by November.
The company, Medicago, is not on the list you provided. It also seems to be a Pentagon funded biotech company so trying to understand how credible this news may be (I'm sure there are many unscrupulous companies trying to claim a miracle cure at this point!)
A reasonably opportunity to throw money at the problem would be to fund speculative production ramp-up for likely candidates ahead of approval, this should not be left to the invisible hand alone.
There are many variants of the flu. Most of them are well-enough understood to vaccinate against, and most of those have an already-tested-and-approved vaccine. The yearly flu vaccine is a combination of those vaccines for the strains the public health experts think are going to be an issue that season.
Sometimes they get it right. Sometimes they don't, and we have a bad flu season (see also: this year).
Here's a Planet Money rerun that talks about how they make the regular flu vaccine: https://www.npr.org/2020/03/06/812943907/episode-977-wheres-...
Transcript: https://www.npr.org/transcripts/812943907
However the Chinese seem prepared to cut corners on the testing and that:
"Coronavirus vaccine could be ready by April, Chinese officials say" https://nypost.com/2020/03/10/coronavirus-vaccine-could-be-r...