I've never heard of them "Tsolid". I have, and frequently, heard Tsalel and Tsolel, both come from the Hebrew, biblical name Betsal'el.
When I try to imagine someone saying Tsalel or Tsolel, it sounds very similar to Tsolid.
Maybe someone misheard, maybe someone misread, or, maybe it was a mispronunciation by an older sibling that stuck as nickname.
If this were my family, I'd say it was extremely probable it's the same person.
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Odeda Zlotnick
Jerusalem, Israel.