Upon looking at the Tallahatchie marriage files, there are two Boisclair listed:
The page number where the marriage is listed in the title:
Tallahatchie Marriages
Tallahatchie County Marriages-1866-1871
District I-Charleston Mississippi

There are 486 Marriages listed for this book.

204 Boisclair, Henry Brown, Rena 07-11-1868

439 Boisclair, Jas. Harper, Sue 08-31-1871

I see no Rena Boisclair or Mrs. Boisclair interred from the transcription on Beauvior Cemetery.

Thank you all for your help!