Hello there, @dominic1.
Thank you for taking the time to reach out to us here on the Community page. I'm here to help share information about projects.
As of now, adding these fields fields (Start Date, Expected completion date, and others) isn't available in QuickBooks Online (QBO). However, I'll take note with this and pass along the suggestions here on my end. In this way, our product developers/engineers will take a look and work on with this.
For additional reference about projects, you can read this article: Projects FAQs.
You can also check our help articles in case you have any other QuickBooks concerns in the future: Help articles for QuickBooks Online.
Please feel free to add a comment below if you have any other questions about projects. I'm just a post away to help you!
We will raise a product enhancement request in relation to your requirements for projects, we also encourgae you to leave feedback from within your account.