Hello,
I was looking at various parish registers, but without result. Hosna family was in Radetice, Smilkov, Kouty or Borovany etc., it will be maybe a relative, but it is not your John Hosna. Information about sister of John Hosna really interested me, because I found:
Anna Hosna b. 1879 - 1880 (sister of Josef), m Anthony Jancsek b.1884 in 1907 at St. John Nepomuk Catholic durch in St.Louis…info on marriage rec indicates her father as “Joannis” Hosna and location of Ounuz, Sedlesny, Bohemia or similar spelling. On http://www.cgsi.org/research/message-board/post/214522 Are you searched for a place Ounuz?
I have no big doubt an indication of the village Radimov. Birthplace of Josef (1879) per ship record is Cichov….. but the hypothesis: near the village Uonuz is Cunkov, if incorrect written, very similar to a name “Cichov”. But I do not rule out even the "Moravian" Cichov!
Ounuz (49°32'22.198"N, 14°30'32.372"E) is a small village, part of municipality in the district Jistebnice near town Tabor. Located about 6 km north of Jistebnice. But historically the parish books were in Sedlec (today Sedlec-Prčice), not on-line yet.
You wrote: my husband was just always told the family lived near Praha, but nothing more specific. On boards.ancestry.com. Ounuz is this a movement towards Prague…
In parish book on http://actapublica.eu/ Sedlec-BN 06, born and bapt. in 1790 – 1801:

b.11.10.1790 in Aunus = Ounuz Nr.5 is Catharine Hosna, father Hosna Josef,mother Anna
b. 6.2.1794 in Aunus = Ounuz Nr.5 is Franisek Hosna, father Hosna Josef,mother Anna
b. 19.9.1796 in Aunus = Ounuz Nr.5 is Anna Hosna, father Hosna Josef,mother Anna
b. 7.5.1799 in Aunus = Ounuz Nr.5 is Jan Hosna, father Hosna Josef,mother Anna
Parish books from 19th century not yet available.
I looked to preliminary sketches to the Land Cadastre (ca. 1835- 1840) and in house Ounuz Nr5 I see as a owner: Wzl (=Wenzel) Hoschna (=Hosna)! It is attached to this message. Yellow color on the map is of wood construction. The house still stands there, as it was built in the 19th century.
What's more! I found a picture painted in 1932, where is written: "At the Hošna house in Ounuz", drawn by Mr. Jaroslav Spirhanzl (incidentally, a very interesting man ...).
Blazek family lived in the village Vratisov and also in Sedlec according to parish registers from Nadejkov in the late 18th century - it is also the same area.
Unfortunately, they are still just assumptions, based only on one single information, I do not have a direct connection.
Maybe it will help
Best Regards, David
PS.: Anthony Jancsek b.1884 in Hohenleipa (per ship record Ellis Isl.NY) = Vysoka Lipa is a village in the district Decin (50°51'28.845"N, 14°21'4.762"E).