Here are some name suggestions based on the provided information, categorized for different stylistic approaches:

Classic Style:

• Male: Arthur Blackwood, Silas Thorne, Reginald Graves, Bartholomew Bloom
• Female: Seraphina Green, Agnes Withering, Theodora Nightshade, Lilith Bloom

Modern Style:

• Male: Jaxon Reed, Kaelen Thorne, Rhys Blackwood, Damon Bloom
• Female: Willow Graves, Raven Nightshade, Ember Green, Skye Withering

Unique Style (incorporating plant/floral elements):

• Male: Nightshade Bloom, Thorn Blackwood, Cypress Reed, Wisteria Graves
• Female: Petal Thorne, Ivy Nightshade, Poppy Green, Belladonna Withering

Names reflecting a duality (florist/killer):

• Male: Caleb Bloom (Caleb suggests innocence, Bloom contrasts with the violent nature)
• Female: Rose Thorne (Rose is beautiful, Thorne suggests darkness)

These names aim to capture the contrast between the seemingly innocent profession of a florist and the brutal reality of the killer's actions. The names incorporate elements of nature (plants, flowers) and darker connotations to reflect the character's duality. Consider the overall tone and style of your story when making your final selection.