To get columns with heading and content aligned top and button aligned on the bottom: use an inner section for the heading and content, and set the column vertical alignment to space-between.

Heading Text Here

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.

Heading Text Here

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus.

Another Heading Here

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis.

A Long Heading Here That Wraps

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus.