Welcome survey questions are currently configured via code by the WMF Growth team. The main objective of the survey is for the responses to back features like the [[ https://phabricator.wikimedia.org/T213990 | newcomer homepage ]], which can be personalized based on what the newcomer is trying to accomplish, as stated in their welcome survey.
But it still may be useful to allow communities to configure their own questions/responses on the survey. For instance, if a community is making a big push for Wiki Loves Monuments, it would be valuable for them to know how many newcomers are creating accounts because of that push, or perhaps to even give a different experience to newcomers who give that response.
Some concerns:
* How to make sure that any configurations don't break features that rely on certain welcome survey responses.
* How to detect or monitor whether alterations to a welcome survey affect activation rates. For instance, an extremely long survey might deter newcomers from completing it and may even cause them to leave the wiki.