Iberian + Brazilian cross-border, multi-store Magento PT + ES + BR?

Magento’s multi-store architecture handles PT + ES + BR cleanly because all three share Romance-language proximity but have radically different tax/payment/legal regimes:

• Single Magento backend, 3 stores, one for PT, one for ES, one for BR. Shared catalogue, separate URLs (yourbrand.pt / yourbrand.es / yourbrand.com.br) or one domain with country selector.
• Per-store currency, EUR for PT + ES, BRL for BR. Magento currency_symbol + auto-rate update from XE / OXR.
• Per-store tax, PT IVA 23%, ES IVA 21%, BR has ICMS + IPI + PIS/COFINS (state + federal, ~17-19% effective). BR requires a completely different tax engine, we usually integrate Avalara Brazil or TaxWeb.
• Per-store invoice, SAFT-PT for PT (mandatory since 2013), SII for ES (mandatory since 2017 for > €6M), NF-e for BR (mandatory). Three different e-invoice pipelines.
• Per-store payment, PT (MB WAY + Multibanco), ES (Bizum + cards), BR (PIX + boleto + Mercado Pago).
• Per-store legal, LPDP (PT) + AEPD (ES) + LGPD (BR). Three privacy regimes.

180M+ Lusophone speakers across PT + BR + Angola + Mozambique. Architecture decided in the audit step.