"AFAIKtwo Tararawa Class ships are in reserve Peleliuonly since 2015 so she might be a gap fill option."
Yes Nassau LHA4 has been in reserves since 2011 and Peleliu LHA5 only since 2015 - Peleliu is only a few years older than BHR and could probably be reactivated for a small part of the time & cost of a rebuild .
Even though they weren't a great success as a class she could operate Harriers and fill a gap if they feel they need to.