The demand for various links seems to be convoluting this post a bit, so here are some of them (Note: there could be other kids):
Johannes LangwasserX 08 Nov 1836 Hefersweiler, Pflaz, Bavaria (
https://www.familysearch.org/ark:/61903/3:1:3Q9M-CSJB-XGX3?i=80 )
Catharina Ecker-
Johannes b May 1832 (
https://www.familysearch.org/ark:/61903/3:1:3Q9M-CSJB-XGX3?i=80 )
Catharina b Feb 1834 (
https://www.familysearch.org/ark:/61903/3:1:3Q9M-CSJB-86R5?i=108 )
Peter b 18 Aug 1838 Hefersweiler, Pflaz, Bavaria
Adan b 28 May 1836 Hefersweiler, Pflaz, Bavaria
Elisabetha b 16 Jul 1840 Hefersweiler, Pflaz, Bavaria
Barbara b 5Jun 1842 Hefersweiler, Pflaz, Bavaria
Heinrich 30 Jul 1844 Hefersweiler, Pflaz, Bavaria
Heinrich b 9 Oct 1850 Hefersweiler, Pflaz, Bavaria
Jacob b 5 Aug 1853 Hefersweiler, Pflaz, Bavaria
Johannes LangwasserX 01 Aug 1860 Hefersweiler, Pflaz, Bavaria (
https://www.familysearch.org/ark:/61903/3:1:3Q9M-CSJB-XL2Y?i=184 )
Dorothea Buehler/Bühler-
Johannes b 2 Mar 1861 Hefersweiler, Pflaz, Bavaria, bap 10 Mar 1861 Evangelisch,Niederkirchen Otterberg, Pflaz, Bavaria
Adam b 9 Jun 1862 Hefersweiler, Pflaz, Bavaria (
https://www.familysearch.org/ark:/61903/3:1:3Q9M-CSJB-8DZP?i=305 ), bap 22 Jun 1862 Evangelisch,Niederkirchen Otterberg, Pflaz, Bavaria
NN b/d 26 Dec 1963 Evangelisch, Niederkirchen Otterberg, Pflaz, Bavaria
Karl b 20 Dec 1864 Hefersweiler, Pflaz, Bavaria, bap 26 Dec 1864 Evangelisch,Niederkirchen Otterberg, Pflaz, Bavaria
Catharina b 29 Apr 1866 Hefersweiler, Pflaz, Bavaria
Christina b 6 Apr 1868 Hefersweiler, Pflaz, Bavaria
Jakob b 6 Jan 1870 Hefersweiler, Pflaz, Bavaria, died Feb 1870 (
https://www.familysearch.org/ark:/61903/3:1:3Q9M-CSJB-XLYY?i=527&cat=253262 )
Katharina bap 9 Jun 1872 Evangelisch,Niederkirchen Otterberg, Pflaz, Bavaria
Heinrich bap 26 Jul 1874 Evangelisch,Niederkirchen Otterberg, Pflaz, Bavaria, d 18 May 1877
Karl b 1876 (
https://www.familysearch.org/ark:/61903/3:1:3Q9M-CSJB-8Z73?i=21&cat=253262 )
Heinrich b 1881 (
https://www.familysearch.org/ark:/61903/3:1:3Q9M-CSJB-8CSR?i=125&cat=253262 )
(Note: Civil Registration birth years 1874 and 1875 are missing and baptisms are not accessible from home)
I believe Adam 1862 is currently your best bet, so I haven't bothered with the after-marriage kids of the following couple. I did have a look for pre-marriage kids, but nothing obvious turned up:
Peter LangwasserX 27 Jul 1865 Hefersweiler, Pflaz, Bavaria (
https://www.familysearch.org/ark:/61903/3:1:3Q9M-CSJB-XLP5?i=215 )
Catharina Weber