To be honest I do not see how the Foundation can advise you as they do not know anything about your set-up or processes / software are.
The legal liability that would put the Foundation under would not be taken on by any company and to be honest I think it should sit with the manufacturer of the final device (as does copyright, IP checks, trademarks etc).
The company has a contact for more info and a partnership with their certification partner UL - that’s more than a lot of manufactures I’ve worked with do.
Edit: As for your use case: I believe yes it would need testing as it is now longer the same configuration as the original items that have been given the certification - but I’m not qualified to tell you one way or another and this can be ignored or followed at your own risk. If in doubt contact the regulatory body on the country you wish to manufacture and those you wish to sell into.
Need Pi spray - these things are breeding in my house...