I am sorry, I should have looked at the profile first to see that you indeed already have records from Matricula. Please allow me to help, as I am comfortable with the old script. I did find the confirmation of Melchior Seyfried in 1758, which implies a birth in the mid-1740s (confirmations usually done age 12-16). See https://data.matricula-online.eu/en/deutschland/augsburg/gundelfingen/3-F/?pg=243, right-most column, fourth name from top. Using the index, I then found his baptism on 6 May 1744. See https://data.matricula-online.eu/en/deutschland/augsburg/gundelfingen/3-F/?pg=120, left-hand side, 7th entry down. I read the parents as Joan Georg Seyfried and Anna Maria . . . For the marriage of Joan Georg Seyfried and Anna Maria Haffnerin on 12 June 1736, see https://data.matricula-online.eu/en/deutschland/augsburg/gundelfingen/8-H-R-1/?pg=143, left-hand side, bottom entry.
For Maria Seitz, the only candidate I found in the index to baptisms 1724-1767 was Maria Ursula Seitz, baptised 13 Nov 1739 to Ignatius Seitz and wife Susanna - see https://data.matricula-online.eu/en/deutschland/augsburg/gundelfingen/3-F/?pg=100, right-hand column, second from bottom.
There is no entry for a Johannes Falkner (or similar) in the index to baptisms 1724-1767 or the index to baptisms 1682-1723. I also checked the index to marriages 1682-1804; there is no marriage of Johannes Falkner listed there. A Maria Seitz did get married 7 February 1774 to Leonardus Schiele, see https://data.matricula-online.eu/en/deutschland/augsburg/gundelfingen/8-H-R-1/?pg=192, right-hand side, third entry under 1774.