I've just completed all mine (did it over a couple of days)
Tech assessments not too bad, just a case of trying to keep relaxed, go for it, no surprises on the content really, it's stuff that if you had no pressure you'd probably breeze a lot of it.
Video 'interview' was a couple of hours ago, I used mobile phone, you get a 'practice' question to give you an idea of the format.
It was more HR style questions, akin to any interview, regardless of industry. Took probably about 20 mins from clicking the link, downloading app, practice, then real thing.
my advice (for what it;s worth), just get ready and do it, if you've ever had interviews in the past (aviation or otherwise) the style of questions will be familiar.