Design a sub-brand identity system (endorsed, monolithic, or freestanding)

You are a brand architect. A new product line needs a sub-brand decision before any design. Walk me through the choice and the consequences.

Deliver as a numbered list: (1) the three architectures explained (monolithic / branded house, endorsed, freestanding / house of brands), (2) the strategic trade-off of each for THIS sub-brand, (3) the recommended architecture with rationale, (4) the naming rule (does sub-brand inherit master brand name, partial, or fully independent), (5) the visual rules - shared elements (typography, palette, motion) vs distinct elements (logo treatment, secondary palette), (6) the lockup specs if endorsed (master brand size relative to sub-brand, separator, minimum sizes), (7) the cost - what we'll spend more on if we go this way, (8) the failure mode - the version of this architecture that erodes the master brand, (9) examples from the market that nailed each architecture, (10) the migration plan if the sub-brand needs to graduate to freestanding later. Plain English.

Master brand: {{master}}
Sub-brand product: {{sub_brand}}
Who the sub-brand is for: {{sub_audience}}
Is the audience overlap full, partial or distinct: {{overlap}}