Proposal dinner - how much of this can I prepare in advance?

Hi All

I am planning on cooking my gf a three course meal and proposing that same night, and I wanted to ask around how much of the main I can prepare in advance of the evening:

Mains

Herb crusted rack of lamb

Fondant Potatoes

Spinach

Canelleni bean puree

Lamb and rosemary jus

Is it possible to prepare the puree in advance at all?

Also...I need some suggestions for a starter?! I was thinking scallops in parma ham but I find it difficult to find the big king scollops near where I live...

Any help appreciated. (I have never attempted any of the above before).

Edit: after bit more research I have expanded my starter options to burrata with green pea gazpacho, or red Thai curry mussels.

Edit 2: I have decided on Gazpacho Verde with Burrata as the starter - thanks to everyone for their awesome advice. I will update this thread in a couple weeks when I do my test run, and then a couple weeks after that with the (hopefully) successful night!

What do you guys think?

Thanks