Unfortunately I don't know

The clasp on the bracelet is a pin buckle. A pin buckle means that the strap has a mechanism that allows the strap to be adjusted without holes in the strap itself. Instead, the strap is secured by a spring mechanism that clicks into the watch holder. This means that there are no holes in the strap itself to adjust it.

No, the wristband does not fit Venu 3

Yes, perfect even

Like in the first picture.

The lug width is important for a new strap. This is 20 mm for the Vivoactive 3. This means that the strap fits the watch.