With a Sept UY, you have until April 30th to bank points. That means that any trip that would be canceled at least 31 days in advance (less than that the points are in holding status which are different rules) that fall within those dates, will put the points back into your account in the same way they were used in the reservation. So, any current UY points would still be bankable for the Feb and April trips.
For the June trip, if you had to cancel any later than April 30th, those points would be stuck in your 2019 UY and would have to be used by August 31st, 2020. Any points that would be borrowed for the Feb, April, June trip would also need to be used by August 31st, 2020.
Any cancellation less than 31 days from check in, points are in holding, will expire August 31st, 2020 and can only be used to book vacations 60 days or less from check in. The Nov 2020 trip is in your 2020 UY, so as long as that one is canceled 31 days or more from check in, you have plenty of time to bank points, or use up any borrowed points that would expire August 31st, 2021.
