The Book I Read 私が読んだ本

私たちが晩ご飯を食べた describes レストラン the same way 静かな or 有名な would, an entire clause working as one big adjective. The subject of that inner clause takes が, never は, exactly the rule you met in が・は.

Tense inside the relative clause is independent of the main sentence’s tense, past, present, or a want like 行きたい can all describe the noun regardless of when the main clause is set, since the clause is just modifying the noun, not making its own separate claim about time.

Introducing a person this way, name first, then a relative clause naming a key trait, is an extremely common pattern in conversation, packing identity and description into one smooth sentence.