I read the provisions of 37 C.F.R. 1.57 to require that a statement referring to an earlier application as being incorporated by reference must be in the application-as-filed.
a reference made in the English language in an application data sheet in accordance with § 1.76 upon the filing of an application
but the application contains a claim under § 1.55 for priority of a prior-filed foreign application or a claim under § 1.78 for the benefit of a prior-filed provisional, nonprovisional, international application, or international design application, that was present on the filing date of the application,
and then there is this provision regarding “Essential material” that limits what can be incorporated from any foreign application or patent even with proper mention in your application-as-filed -
Essential material” may be incorporated by reference, but only by way of an incorporation by reference to a U.S. patent or U.S. patent application publication, which patent or patent application publication does not itself incorporate such essential material by reference.
The only bright spot I see is in the details of § 1.55 Claim for foreign priority which talk about a delayed filing for foreign priority and a mention in CFR 1.57
(3) If an application is not otherwise entitled to a filing date under § 1.53(b), the amendment must be by way of a petition pursuant to § 1.53(e) accompanied by the fee set forth in § 1.17(f).
You should consider getting help from a registered practitioner and also consider what claim coverage you can salvage without the figures but with whatever text describes the aspects illustrated in the figures without actual reference to the figures.
I'm assuming your public demonstration was within a year of filing and that it was documented in some way at the time. Depending on the timing of the public demonstration disclosure and how it was documented it is conceivable that you could declare that some things demonstrated are covered by the one year grace period and some things are not. I have never heard of that and if you engaged a patent attorney or registered agent they might research the specific issues around your facts and offer some hope.