This giant family with eyes on Frobisher is a bit of much-needed comic relief. They're not intending to be funny, but Frobisher's observations about how hard the van de Veldes try to appear cultured are Cloud Atlas's LOL moments.
First, they stand on the stairs Brady Bunch-style and singing "Greensleeves" when Frobisher enters. Then he's questioned by "a hydra of head named Marie-Louise, Stephanie, Zenobe, Alphonsine, and [he] forget[s] the last" (10.2.10). Did you catch those names? As a group, they're just as ridiculous back then as they would be now.
Frobisher's pretty cruel, calling Marie-Louise a "spoony-eyed little heifer" (10.2.25) and the whole group a "family of porkers" (10.2.10), but it's impossible not to laugh when, for instance, Marie-Louise thinks Sherlock Holmes is a real person—to which Frobisher responds, "I [don't] know Mr. Holmes personally, but he and David Copperfield could be seen playing billiards at my club every Wednesday" (10.2.10). Maybe Jane Eyre was his governess.