In regards to the names, the first thing you will want to do is verify the LNAB to find out which usage is correct, Van Hook, Vanhook or van Hook.
And yes, while we do want to merge to the lowest possible number, that should be the correct lowest possible number. As an example, if the LNAB is verified as "van Hook", you would not want to merge them into "Vanhook" just because the number is lower... you would merge them all into the lowest possible "van Hook" number (if there are multiple of the same spelling).
In regards to sources, this information can be merged along with the normal profile information. As an example, if the profile for "van Hook" contains the correct LNAB, but has no data or biography - the name "Vanhook" has the incorrect LNAB, with sources and a biography - then the merge process will transfer all of the information you choose during the process.
Building on what RJ Horace stated, I would not suggest adding a new profile to make a correct LNAB. If the correct LNAB does not yet exist - you can take the most complete profile and change the LNAB on that profile as long are you manage the profile.
In the event that you do not manage all of the profiles or are on the trusted lists for said profiles - you will need to submit merge requests and wait on a response from the applicable managers of the profiles.