This makes no sense to me. Nobles are not peasants done good any more than guilders are craftsmen done good. Nobles and guilders (and priests and wizards) are the same people, siblings, cousins, and other equal relations.
Take Dhoeosne. The guilders are all of the same bloodline strength as the counts are. One of them, Mheallie Bireon, is substantially greater. Guilders and Counts form a common marriage pool. They are cousins, in-laws, and so on.
The medieval church was run (Bishops, Archbishops, and Cardinals) by the nobility and very talented commoners. The Church leaders socialized, identified, and cooperated with the nobility.
Likewise guilds would work the same way. Not by rising from the ranks to leadership any more than the church, but by providing opportunities for nobles to direct an organization.
The medieval social construction of status was based on one’s family, one’s marriages, one’s offices, and one’s accomplishments. I see no reason to assume Cerilia is any different. Bloodlines are real, manifest, and directly useful. One’s family and one’s marriages (and therefore the basis of one’s heirs) may or may not be more important, but its hard to imagine how a character with two minor blood abilities can look at another character with two minor blood abilities and think, he’s lowly. Guilders are no less educated, sophisticated, or worldly.
Historically economic enterprises were not united into domains the way church and realm were, so that nobles could not find their social equals in the world of commerce, until the 19th century when it was possible to find men who owned so much, so many ships, so many factories, but this is why you can’t just use historical analogies without considering how Cerilia is different from our historical experience.
When we find occasional analogs, they have shifted from being obvious guilders to being aristocratic. But I contend there is no difference. The Medici were a dynasty, who merely happened to be bankers, then bankers and executives in a Florentine republic, then Grand Dukes of Tuscany, marrying into French (Catherine, Marie) royalty and Austrian (Claudia and Anne Marie) as well.
England experienced an unusual relationship between nobles and merchants that was unique to England because of its inheritance system, its commercial success, and its different definition of nobility. Case 1 and 3 don’t exist anywhere in Cerilia.
Money seeks land because it seeks a safe store of value that is a hedge against inflation and price changes. Land seeks money because land is not at all liquid. If we conjecture a guild domain, with people clearly manifest as scions at the head, its hard to imagine why they were not be seen as total equals.