Hi S Accounts,
You can register without a NINO by using the manual SA1 form and a temp NINO will be allocated once the form is processed.
Register for Self Assessment if you are not self-employed
A correspondence address can be used. Once you have the UTR, you can then send in a paper SA100 and SA109. if filing online, yes the residence status section would need to be completed as this is the SA109 part.