Hey Casey, this is one of the areas where things get a little weird because the W3 doesn’t actually have any say over the ADA guidelines, it is more than the ADA guidelines adopted the WCAG 2.0 guidelines as just that, a guideline to help. As far as I know, the tool you’ve linked to hasn’t been used in any judgements I’m aware of. Usually when it comes down to making a decision on if something is/isn’t compliant they have people use the actual PAWS tools and show what elements do/don’t work as intended or are otherwise inaccessible. Hope this helps!

Time zone and how it affects a timeline and budget is a direct result of a freelancer’s geography. If your designer is 10 hours ahead or behind your timezone, communication will be slower. This affects your timeline, because you’ll probably receive a response 24 hours after you send your question. Some designers will work during the time zone of their regular clients, so ask the provider about their office hours.
For discussion’s sake – while I don’t know the specific nature of your videos, my guess is that they might be demonstrating various techniques or other content in which simply hearing the audio of the video wouldn’t deliver the full context of the content. If making that content accessible is something you’d want to do, you’d likely want to start with a written description of what takes place in the video. Beyond that, high contrast vector images or diagrams showcasing specific parts of the technique would certainly help.
This title requires telephone and Internet companies to provide a nationwide system of interstate and intrastate telecommunications relay services that allows individuals with hearing and speech disabilities to communicate over the telephone. This title also requires closed captioning of federally funded public service announcements.  This title is regulated by the Federal Communication Commission. 
Until the ADA is updated to address the special case of website accessibility, or the Department of Justice releases its website accessibility regulations, complying with WCAG 2.0 Level AA is the best way to ensure that people with disabilities have equal access to your website. The overview below is a great starting point about meeting the WCAG 2.0 Level AA recommendations.
A. The ADA permits an employer to refuse to hire an individual if she poses a direct threat to the health or safety of herself or others. A direct threat means a significant risk of substantial harm. The determination that there is a direct threat must be based on objective, factual evidence regarding an individual's present ability to perform essential functions of a job. An employer cannot refuse to hire you because of a slightly increased risk or because of fears that there might be a significant risk sometime in the future. The employer must also consider whether a risk can be eliminated or reduced to an acceptable level with a reasonable accommodation.
This was a case filed before The United States District Court for the Eastern District of Michigan Southern Division on behalf of the Michigan Paralyzed Veterans of America against University of Michigan – Michigan Stadium claiming that Michigan Stadium violated the Americans with Disabilities Act in its $226-million renovation by failing to add enough seats for disabled fans or accommodate the needs for disabled restrooms, concessions and parking. Additionally, the distribution of the accessible seating was at issue, with nearly all the seats being provided in the end-zone areas. The U.S. Department of Justice assisted in the suit filed by attorney Richard Bernstein of The Law Offices of Sam Bernstein in Farmington Hills, Michigan, which was settled in March 2008.[66] The settlement required the stadium to add 329 wheelchair seats throughout the stadium by 2010, and an additional 135 accessible seats in clubhouses to go along with the existing 88 wheelchair seats. This case was significant because it set a precedent for the uniform distribution of accessible seating and gave the DOJ the opportunity to clarify previously unclear rules.[67] The agreement now is a blueprint for all stadiums and other public facilities regarding accessibility.[68]