I'm considering whether I should purchase Lightroom 5 as a standalone, or subscribe to the photographer creative cloud.
The only reason I am hesitant towards the subscription, is the consequences of cancelling my membership or my membership expires.
Do I still have access to all the functions of Lightroom when my membership expires? Or do I lose ownership of everything?
You do not lose your images. They are yours, and will always be yours. If you decide to cancel your creative cloud subscription then the develop module of Lightroom will be completely disabled. You will not be able to use Lightroom to make any adjustments. If you are thinking of subscribing with the intent of canceling at a future date you might consider purchasing a standalone license. It is the same program. The only thing to consider is that every time there is a major upgrade (like from version 5 to version 6) it will be necessary for you to purchase the upgrade.
That's not quite right. You can use Lightroom for everything except go into the Map and Develop modules which are disabled,. You can make adjustments via Quick Develop and presets.