Understood, @skowronek. I approved the topic in the moderation tool, but for some reason it still appeared as deleted.
To clarify, by "Create Deal Management Dialog," are you referring to the UI settings I depict below, located in Settings > Sales > Deals > Set the properties your team sees when creating deals > Manage?
If so, there is no way to retrieve or alter these settings via the Deals API at this time. I can't think of a way to match the required fields in your external form to an account's settings without the involvement of a user in the corresponding account.
While I certainly see value in such a feature, I could not find any similar existing feature requests on the HubSpot Community Ideas Forum. If you feel so inclined, I recommend posting a new request on the forum for our product teams to see. If you share a link here, I will be happy to upvote it.