#web-to-lead fyi, Salesforce doesn't allow lookup-fields. I am finding this out the hard way. I've spent a few hours attempting to use hidden fields to assign Advisor and/or OwnerId. I found several posts saying to use hidden custom fields instead, but I couldn't found out why.

I stumbled upon a note from 2007 saying you can't use lookup fields. Thought others might like to know. 

https://ideas.salesforce.com/s/idea/a0B8W00000GdVcSUAV/autopopulate-value-in-lookup-field-on-webtolead-form