Website Micro-Animation from PNG (After Effects / Lottie)

I have a transparent PNG illustration (large vintage camera with a crowd of small cut-out figures) that I use prominently on my website.
I’d like a subtle, elegant entrance animation created for web use. The idea is that the small figures gently gather into position beside the camera on page load. The tone should be restrained and editorial — no cartoon motion, no bounce effects. Very simple and classy.
The animation should last approx. 3–4 seconds, play once, and then hold on the final still frame. I will supply the PNG. The designer will need to separate the crowd into logical groups for animation.
Deliverables:
– Web-ready format (Lottie JSON preferred, or lightweight WebM with transparency)
– Optimised for fast website loading
– Smooth easing, no gimmicks
Please share examples of subtle motion graphics work.
Please confirm you are comfortable delivering either a Lottie animation or transparent WebM optimised for web.