Yes. And to be a member of the Order, the vampire has to be influential and involved in anything that has to do with holding power. Whether they are counts, countesses, nobles or aristocrats or even kings. They have to have an unblemished reputation and to be loved or at least respected by society. Small wonder most of the named NPC's we meet in Cyrodiil that are vampires are wealthy in a way, or at least come off that way; Seridur, for example, is respected by the community. So much so that Roland said everyone would take his side instead of his on the subject about who is the real vampire. Jakben Earl of Imbel is also known to have had a flawless reputation among the people, and he was just a busy reclusive man who people believed had a rare "skin condition." In any case, he's a former thief turned nobleman. Lord Lovidicus is obvious, I am sure you read his journal. Janus Hassildor is the highest ranking vampire we meet. The Pale Lady seems to have been a proper lady, perhaps one of Rona Hassildor's friends as she collects blood for her.
In any case, you get my point. I don't think any common man living in poverty who was a vampire would be counted among the clan. They probably consider their members wisely.
In regards to feeding, I agree. If a member of the Order had land and territory, he could easily build underground caverns and lairs that would house unconscious cattle. It would not draw attention if criminals from prisons or bandits or even beggars are pulled away. Since they are low-lives, common rabble of society, they wouldn't be as missed as say a daughter of a count or nobleman or someone well-known and important. Blood-farms that would serve as a "bank" for vampires who travel around Cyrodiil in business trips. They make a stop at one of these underground lairs, which was bought off in their own territory, take a drink to continue their lives.
The reason I think the Order saw that the Whet-Fang were smart to use sleeping, comatose captives is not only because they prefer to feed on unaware victims, but also that feeding on mortals on the piece meal basis was too inefficient. They might take a bite or two here and there, but why kill your prey when you can keep him alive and without any struggle? After all, it is a sleep they cannot awaken from. Not only would the feeding be easier, more civil than taking bites on awake and paralyzed prey such as the Volkihar, it would mean less escapees and resistance who could potentially draw needless attention.
Just pick away bandits and beggars, clean them up, put them to sleep and set up the cattle farms. Only true members of the Order would be aware, making use of these underground cattle cells that would be secret from society to facilitate travel and lessen the need to kill people.