Here are some references on the palaeobiogeography of the Ellimichthyiformes:
1. Alvarado-Ortega, J., E. Ovalles-Damiȧn, and G. Arratia. 2008. A review of the interralationships of the order Ellimmichthyiformes (Teleostei: Clupeomorpha); pp. 257–278 in G. Arratia, H.-P. Schultze, and M.V.H.Wilson (eds.), Mesozoic Fishes 4 – Homology and Phylogeny. Verlag Dr. Friederich Pfeil, Munich, Germany.
2. Murray, A. M., and M. V. H. Wilson. 2013. Two new paraclupeid fishes (Clupeomorpha: Ellimmichthyiformes) from the Late Cretaceous of Morocco; pp. 267–290 in G. Arratia, H.-P. Schultze, and M. V. H. Wilson (eds.), Mesozoic Fishes 5 – Global Diversity and Evolution. Verlag Dr. Friederich Pfeil, Munich, Germany.
3. Forey, P. L., L. Yi, C. Patterson, and C. E. Davies. 2003. Fossil fishes from the Cenomanian (Upper Cretaceous) of Namoura, Lebanon. Journal of Systematic Palaeontology 1:227–330.
4. Zaragüeta-Bagils, R. 2004. Basal clupeomorphs and ellimmichthyiform phylogeny; pp. 391–404 in G. Arratia, G. Tintori, and A. Tintori (eds.), Mesozoic Fishes 3 – Systematics, Paleoenvironment and Biodiversity. Verlag Dr. Friederich Pfeil, Munich, Germany.
So far, the earliest fossil record of the ellimmichthyiforms is known from the Neocomian sediments of Brazil (Scutatuspinosus itapagipensis, originally described by Silva Santos & Silva Corréa (1985) as Clupeidae insertae sedis). There's also Ezkutuberezi carmenae from the Valanginian - Barremian of Spain (not quite a Gondwanan species unless you allow for migrations). Here are the references to the original descriptions of these two earliest species:
1. Silva Santos, R., and V. L. S. Corréa. 1985. Contribuição ao conhecimento da paléoictiofaunula do Cretáceo no Brasil; pp. 169–174 in A. de Campos, C. S. Ferreira, I. M. Brito, and C. F. Viana (eds.), Coletánea de Trabalhos Paleontológicos, SérieGeologia 27(2). Ministério das Minas e Energia-Departamento Nacional de Produção Mineral, Rio de Janeiro, Brazil.
2. Poyato-Ariza, F. J., M. A. López-Horgue, M. A. Garcia-Garmilla, and F. Garcia-Garmilla. 2000. A new Early Cretaceous clupeomorph fish from the Arratia Valley, Basque Country, Spain. Cretaceous Research 21(4):571–585.
In case you're still looking for salmoniform/elopiform-related references, I can suggest these two articles to start off:
1. Dornburg, A., Friedman, M., Near, T.J. 2015. Phylogenetic analysis of molecular and morphological data highlights uncertainty in the relationships of fossil and living species of Elopomorpha (Actinopterygii: Teleostei), Molecular Phylogenetics and Evolution, 89: 205-218. doi: 10.1016/j.ympev.2015.04.004.
2. Wilson, M.V.H., Williams, R.R.G. 2010. Salmoniform fishes: key fossils, supertree, and possible morphological synapomorphies; pp. 379–409 in J.S. Nelson, H.P. Schultze, M.V.H. Wilson (Eds.), Origin and Phylogenetic Interrelationships of Teleosts, Verlag Dr. Friedrich Pfeil, München. (full text is available on ResearchGate)
Both have a good overview of each group's phylogeny with information on the extinct taxa including the earliest fossil record; that should be helpful addressing your questions of the paleobiogeo and origin of salmoniforms and elopiforms.