Custom-Fitted Winter Outfit for My Dog

My dog is a small mixed breed with an unusual body shape, and none of the ready-made sweaters or coats I've tried in pet shops fit properly — they either choke her neck, slide off her back, or leave her belly exposed to the cold. I'm looking for someone experienced in sewing pet clothing who can create a piece built around her exact measurements rather than a generic size chart.

I can provide a full set of measurements (neck, chest, back length, leg openings) along with photos from multiple angles, and I'm open to a short video call or a fitting mock-up before the final piece is sewn if that helps get the proportions right. The item should be comfortable for everyday walks in cooler weather, easy to put on and take off without stress for the dog, and made from a soft, durable, machine-washable fabric that won't irritate sensitive skin.

I'd like to discuss fabric and color options together, but I'm generally drawn to warm, cozy materials for a winter sweater or a light waterproof coat for rainy days. If you have experience with Halloween or holiday-themed costumes, I would also love to hear suggestions, since I'm considering a fun costume later in the year as a possible follow-up project.

Requirements:
— Custom pattern built from provided measurements and photos, not a standard size
— Soft, hypoallergenic, machine-washable fabric
— Secure but easy on/off closure (velcro, snaps, or similar)
— Reinforced stitching at stress points (legs, neck, harness opening)
— One fitting adjustment included if the first attempt doesn't sit right