Some quotes from Zak's Q&A on the official team website:
https://www.mclaren.com/formula1/team/z ... a-3166752/
I’m excited that James will be starting in time not to influence the 2019 car on its debut, but certainly to help its progression over the course of the season, and most importantly have him be the ‘father’ of the MCL35.
Finally, we’re making good progress on the sponsorship and partnership front. It’s safe to say, you’re going to see some great new brands on our car on the grid in Australia, so I’m very satisfied with the efforts the marketing and commercial departments are putting in to find us great partners to come on this journey back to winning races.