If you gonna go with using line anchor whatever setup make sure it has a quick release at the kayak end like a cam or clam cleat. Then of course you can have a float on the external part of line in case you have to ditch it in the water and come back for it.

Also have this or a couple of these handy:

https://www.amazon.com/gp/product/B004UD6AP2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Its on a larger side but works really well cutting up to 5/8" rope quickly and under load. You just hook the line and it cuts thru. Practice using it. I have one on my vest and one in the kayak on a bungee close to the anchor cam cleat. Make sure you can use it in any position and without too much thought.