After the OA, I got the invite for the Craft Demo round.

Craft Demo question: All subtrees formed once a node in a given tree is removed.
Question was given a day before, had to prepare the solution & present it to the interviewer.

Prepare all the scenarios asked in the question plus be ready to answer further scenarios like what if multiple nodes are to be deleted. Was also asked what if the nodes had to be dereferenced (actually delete the given node & remove the left / right pointer or the pointer from the parent to the given node).

Followed by a design/coding question
Sum of two huge numbers (without using BigInteger, long etc). Changes to enable subtraction of such big numbers.