If you have a lookup table in place and defined a RegexFeaturizer in your pipeline, the entity extractor does not know how to handle the features created by the RegexFeaturizer if you don’t have some entities with values from the lookup table in your training data.
So, in case you want to make sure your entity extractor extracts entities present in the lookup tables more likely, you need to have some examples in the training data. It does not matter how you handle the form intent in that case. The only thing that matters is that you have some example of entities with values of the lookup table in your training data. You can also put those under the inform intent, if you like.
Does that answer your question?