Help Identifying an Antique Seed Pearl and Diamond Necklace

[panim]

Hello everyone,
I recently purchased an unusual multi-strand pearl necklace and would really appreciate opinions from members experienced with antique and natural pearl jewelry.
The necklace has:

• Many strands of very small cream-colored seed pearls
• Three large floral-style sections made with irregular silver-gray pearls
• Diamond cluster centers on all three floral sections
• Pearl tassels and knotted pearl elements
• A gold-colored clasp marked 14K
• Perforated gold-colored metal backings behind the floral sections, with the pearls stitched or tied through the holes

The seller stated that the necklace may date from the late 1800s and had been passed down through the family. The previous owner was in her 90s, and I was told it had also been worn at a wedding around the 1950s.
The small seed pearls appear to be approximately 1–2 mm, while the larger irregular gray pearls around the diamond centers are roughly 3–4 mm. The larger pearls have a noticeably silvery color and irregular shapes.
I understand that photographs cannot confirm whether pearls are natural or cultured, and I am considering submitting the necklace for X-ray examination and a laboratory report. Before doing that, I would be grateful for opinions on:

1. Does the construction appear genuinely antique?
2. Does this resemble a particular region, period, or jewelry tradition?
3. Do the seed pearls or larger gray pearls visually appear consistent with natural pearls?
4. Does the necklace appear to have been restrung or repaired?
5. Would you recommend testing the complete necklace, or testing representative pearls from each type?

I will attach photographs of the full necklace, close-ups of the pearls and diamond sections, the clasp, the tassels, and the backs of the floral mounts.
Thank you very much for any information or guidance.