I hope that the terms can be re-written to impose some sort of liability on anyone who tries this sort of thing. The only disincentive is the wrath of editors and the foundation, which, frankly, doesn’t amount to much.
1) Label accounts with conflicts of interest if necessary.
Personal accounts that are only personal (and never used in an official capacity for any other organization or entity).
"Professional" accounts for which one or more professional entities (potential conflicts of interest) are disclosed.
2) All work should be submitted to the public domain, or as close to the public domain as possible; and any fair use material clearly marked as such and why. (I believe they already require this, I'm just not a Wikipedia contributor so I've not read their specific guidelines.)
1) It already prohibits paid editing without disclosure. (ctrl-F "Paid contributions without disclosure" in link above)
2) Wikimedia projects require that almost all content be licensed under a free license (ctrl-F "Licensing of Content" in link above). Specifically, text is usually dual licensed under CC BY-SA and GFDL. Wikimedia Commons allows images under any free license. (https://commons.wikimedia.org/wiki/Commons:Licensing)
Exceptions are allowed for fair use content, which needs explicit justification and may only be used sparingly (see https://en.wikipedia.org/wiki/Wikipedia:Non-free_content_cri... for the English Wikipedia's rules, https://meta.wikimedia.org/wiki/Non-free_content for other WMF wikis).