We have one of these that the wife uses to schlep our 6yo daughter and her friends around.  Back can be used for kids or other cargo.
 
	https://lectricebikes.com/products/xpedition-dual-battery?g_acctid=790-567-9445&g_adgroupid=&g_adid=&g_adtype=none&g_campaign=PerformanceMax.branded&g_campaignid=16467002383&g_keyword=&g_keywordid=&g_network=x&nb_adtype=pla&nb_ap=&nb_fii=&nb_kwd=&nb_li_ms=&nb_lp_ms=&nb_mi=129756959&nb_mt=&nb_pc=online&nb_pi=401-01423-C203&nb_placement=&nb_ppi=&nb_ti=&nbt=nb%3Aadwords%3Ax%3A16467002383%3A%3A&utm_source=google-pmax&gad_source=1&gad_campaignid=16467003553&gbraid=0AAAAACvpgWiy5NvhES6HJWhmtbPfLaltV&gclid=CjwKCAjw04HIBhB8EiwA8jGNbeENZibIH9Jiu6hcRXc906dD6VYr5zvr3g8byPEPcxIQGUMVCcNSkBoCjDEQAvD_BwE
 
	 
 
	Lectric is a solid brand.  That said, the beach kills everything and an e-bike doesn't seem that well suited to wet salty air.