Seiichi Samura vs Hazbin Hotel Staff: who would win?

Hazbin Hotel Staff favored — Slight edge (~55%)

Seiichi Samura · Kagurabachi · Base

Tier
9-A, up to 7-B
Attack Potency
Small Building Level, up to City Level
Speed
Massively Hypersonic+, up to Sub-Relativistic
Durability
Small Building Level, up to City Level

Hazbin Hotel Staff · Hazbin Hotel · Base

Tier
9-A, up to 5-B
Attack Potency
Small Building Level, up to Planet Level+
Speed
Ftl
Durability
Small Building Level, up to Planet Level+

A heuristic estimate from normalized VS Battles Wiki stats: tier, attack potency, speed and durability.