Yes, when setting up the notification event, you put what you want to match under either "Text" or "Subtext". For example, I'm a firefighter. My fire department uses a paging app called Active911 to send pages directly to our cellphones. I have Tasker setup to play specific sounds for certain pages, like "FireSF", which is a structure fire, or "All Call", both of which are situations where all available off-duty volunteers are to respond to one of the stations to backfill or provide additional manpower, depending on the situation. In addition to that, I also have it start my scanner app so I can listen in until I can get to a radio at the station. Tasker does those by screening the page text, which I put into the "Text" box under the notification event. You may have to experiment a bit with each notification event to determine whether you want to match "Text" or "Subtext", but it should work for your situation.
Tasker can definitely kill a specific notification by using the notification title.
Basically, when you get the notification you want, there should be the "title" part and then underneath the "text" of the notification. On my stock Samsung S6 the title is slightly larger and bolder than the text part.
I'm not sure if notifications are formatted the same across all Android devices/versions but if you can figure out the title you can then create a task to kill it.
The action you want within your task is Alert>Notify Cancel. Then all you do is enter the title of the notification within the title box/field.
Hopefully knowing the title might help you with the first question.
Just a side note. Have you tried using wildcards in your tasker profile.
On canceling others apps notifications. I came across this app/plugin the other day.
https://play.google.com/store/apps/details?id=com.balda.notificationlistener
It's free and says it can cancel other apps notifications.
I have just had a quick go with it and I managed to cancel a text message notification. Hopefully this might work for you.
I also know there is a AutoNotification app/plugin which extends the functionality of tasker also.
https://play.google.com/store/apps/dev?id=8102570190170276456
Hope these help.