I realise I might be a bit late but I couldn't resist sorry 
The online narrative about these things is a bit clumsy and contains a lot of misinformation or lacks nuance. So you'll have a genuine concept which has been passed through "Chinese whispers" so many times it has become an entirely different point.
FWIW, I have diagnosed ADHD. These are my thoughts on the list in the OP:
- I find it hard to get going or impossible to stop
Can be a personality trait. Could be associated with ADHD, especially if it's severe or causes problems.
- I can put off a tiny task for weeks but worry about it for hours but when I finally complete it it takes 5 minutes
Extremely common pattern in ADHD. I don't know if it's common in people without ADHD. Perhaps it happens occasionally - with ADHD it seems like this is happening constantly to the point that it causes issues in everyday life.
- I can distracted and start cleaning after the shower and suddenly I’ve cleaned the whole house whilst wearing my towel
I can't say I've ever done this personally. But I do recognise the concept of ending up getting pulled into something which seems inconsistent with what I had originally been planning to do, which after a shower, is probably dry myself and get dressed. And I recognise the concept of seemingly mundane or ordinary tasks (like the shower) not getting finished because I have become sidetracked by something else. And the cleaning not having been done in the first place would also be a common theme/pattern - having difficulty keeping up with routine or mundane tasks. So I think that what this is supposed to be is an amusing anecdote which illustrates difficulties with planning, self-motivation and task completion.
- Having a chair covered in clothes
Total red herring, I think almost everyone has this unless they are especially organised/tidy and dislike having clothes on a chair.
- having multiple drinks on the go in the house
Much too small and specific to be anything at all. I would guess this is meant to be an anecdote to illustrate the ADHD difficulty with working memory, which can result in leaving unfinished things (like drinks) all over the place, starting a new thing (e.g. a drink) even though the last one is not finished just because you wanted a change/forgot you had the first one, or possibly sensory seeking (having random cravings for cold/hot/caffeine/sweet/sour/carbonated). But yeah, not really ADHD related even if a lot of people with ADHD would relate to it.
- needing a calender because if not I would forget appointments
I think this is just a normal adult thing. Perhaps a difference between ADHD younger adults (18-24 ish) and non ADHD younger adults - IME most younger people can just remember things without writing them down because they don't have that much on. Once you get older and have 50+ things in your head you can't juggle this any more. People with ADHD get to the point of not being able to juggle everything earlier, and calendars help. Plenty of young adults with ADHD approach calendars like their peers (thinking they are for old people) and get into a mess because of it.