Does SuiteScript allow the creation of custom item options (/custom/itemoptions.nl); custom item fields (/custom/itemcustfields.nl); and custom lists (/custom/custlists.nl)? I’m trying to re-create the Matrix Item Assistant in my own customization and it doesn’t seem like it’s possible

Yes you can use SuiteScript to create those.

Awesome thank you! Seems like

customlist

can be created client-side and server-side, but

itemcustomfield

and

itemoptioncustomfield

can only be created server-side. Also I had to use

itemoptioncustomfield

and not

customrecordtype

. Thanks again!