Inserting multi page, multi-sized PDFs into InDesign

I'm needing to be able to (easily) insert multi-paged PDFs that are of different sizes/orientations into an InDesign doc. I've found the Multi Page Importer Script (https://github.com/mike-edel/ID-MultiPageImporter) which works fantastic if I'm importing a PDF that is all the same size as my ID doc - but is there a way for ID to easily (or automatically) change the page sizes to match the imported doc?

(for example: I'm helping a client set up an RFP template, it is mostly standard portrait letter sized, but he needs to insert spreadsheets that are horiztontal, and maps that are of a larger size. In the past he's exported his RFP as a PDF, then inserted pages into the PDF... however, it messes up his page numbering and table of contents.)

I thought Liquid Layouts might be the key, but I'm struggling to make it do what I need it to.