Aiwass didn't bring much luggage... after all, anything that can be purchased in Avalon is definitely also available in the Holy Nation.
The Holy Nation doesn't have regulations controlling the Transcendents, whether it's ritual materials or alchemical concoctions, they're much easier to buy in the Holy Nation than in Avalon. No matter what they need, it's all the same to buy it once they're at their destination.
As for Sherlock... under Aiwass's advice, he also only brought a set of clothes to change into. However, he carried a good number of books and notes with him, clearly not intending to stop learning and researching while traveling in the Holy Nation.
They entrusted their Codex Books to Bishop Mathers and his family, while Yulia was left in the care of Isabel and Shafiya. Although Ligeia was Avalon's strongest, her personality clearly didn't match the quiet Yulia.
