We know quite a bit about Queen Victoria's views- basically sumned up well here, on Russian marriages. It is harder to say about Alice, especially as her daughters were fairly young at the time of her death. She would most likely have supported the marriages of her daughters, had she been sure that is what they wanted, and it was. She might have had more reservations about Ella's marriage than that of Alix, perhaps more because of what Grand Duke Sergei was like, than the fact he was a member of the Russian Imperial Family.