Zapier Support here. The most common way I see people do this is by starring Slack messages they want to add as Todos. Here's a template that uses Todoist, although there's no shortage of alternatives on that side of things: https://zapier.com/app/editor/template/1580
Outside of that, you can build a zap that triggers on any message and use a Filter step to make sure only messages that meet your criteria(e.g. your keyword) move on to the action: https://zapier.com/help/how-get-started-filters-zapier/
If your ultimate goal is to manage the todo list from inside Slack, there's not a great way to do that with Zapier. Personally, I manually add/delete items in my 'You' channel to get to that type of functionality.
If you can, try setting each portion of the date as a different field for the parser to split out. Then in a zap you could re-assemble the date in the right order so GCal can understand it.
This isn't the first time they've taken this type of action with email account names.
I had an @att.net email address from when I had U-Verse that was essentially Yahoo mail with an ATT address. I thankfully didn't do anything on that account, but I kept it since it was the same user name I have registered on most major webmail services.
I got an email about a year ago that those addresses would be merging with Yahoo, and that my address would now be @yahoo.com. Fine with me, I thought, perfect if I ever wanted to try out Yahoo mail for a spell.
A few months later a get an email about my password being changed. Not good. From there I had about a 15 minute back and forth with someone else trying to get their information(alternate email address, password, security questions, phone number for 2-factor) on the account to lock me out. I prevailed, and in double checking how that person could have gotten access, found something disturbing. This was not my email account. It was mostly dormant, but there were legitimate emails from years ago sent by another person who shares my name.
I contacted Yahoo through their form about such matters, but they never answered. So now I've held on to the address, which I value for preserving my internet identity, but someone else is out of luck in trying to access an account they used sparingly years ago.
This is obviously much worse, as it's intentionally going to result in these types of account ownership issues, but it certainly seems reflective of Yahoo's attitude towards the importance of holding an email address.
It's definitely not a one size fits all situation, there's room for personal preference. Just upthread there's someone lamenting a downside of GTalk and the like. I'm only saying that while the concept definitely sounds a bit invasive, the actual downside is really no different than that of widely accepted alternatives that don't have that stigma.
I equate it to Google Talk. Replace "webcam picture" with "online status" and you can say remarkably similar things about the two.
Both Google Talk and Sqwiggle are meant to facilitate communication and not to be used as accountability tools, but if you don't trust those you're sharing that info with then it could be used that way. Both give out signals of my online status based on my presence, and both can manually be set to a "busy" mode(to the detriment of communication) if I want to not be bothered or "watched". Sqwiggle is obviously a more intimate version of this, but that works to its benefit in lowering barriers to having quick conversations with people you can "see" are available.
On a related, but opposite note, don't make one-click log-ins the only option. I almost assuredly don't want to add another point of access to my Facebook/Twitter/Google data, and would rather manage my Lastpass account than monitor my app permissions across several services.
Depending on the nature of the chats, around a half dozen is my limit. If you've got 1-2 that are only responding to you every 10 minutes or so, or 1-2 have easy general questions, that number could probably push higher. But around 5 conversations that require legitimate investigation and troubleshooting is where I've found you can start to lose engagement.
Actually, many of the tiny house floor plans are designed to fit on a flatbed trailer. Not as easy to manage overnight parking as a van, but pretty feasible.
Outside of that, you can build a zap that triggers on any message and use a Filter step to make sure only messages that meet your criteria(e.g. your keyword) move on to the action: https://zapier.com/help/how-get-started-filters-zapier/
If your ultimate goal is to manage the todo list from inside Slack, there's not a great way to do that with Zapier. Personally, I manually add/delete items in my 'You' channel to get to that type of functionality.