I grew up in Jamaica and ackee is only poisonous if you eat it BEFORE it opens naturally: when it’s not quite ripe. ONLY the yellow, brain-looking parts are edible, not the seeds, and no part of the membrane or pod is safe. To be safe, boil the yellow parts first and discard the water, like you do with cassava.
Here’s some more information
http://wwwchem.uwimona.edu.jm/lectures/ackee.html
https://naturespoisons.com/2014/03/24/ackee-fruit-deadly-and-delicious/
http://www.cooksinfo.com/ackee

I do understand your reluctance because jicama & cassava both scare me!