  An $ab$ $initio$ investigation of the family of molecular compounds TM$_2$$X$
is conducted, where TM is either TMTSF or TMTTF and $X$ takes centrosymmetric
monovalent anions. By deriving the extended Hubbard-type Hamiltonians from
first-principles band calculations and evaluating not only the intermolecular
transfer integrals but also the Coulomb parameters, we discuss their material
dependence in the unified phase diagram. Furthermore, we apply the
many-variable variational Monte Carlo method to accurately determine the
symmetry-breaking phase transitions, and show the development of the charge and
spin orderings. We show that the material-dependent parameter can be taken as
the correlation effect, represented by the value of the screened on-site
Coulomb interaction $U$ relative to the intrachain transfer integrals, for the
comprehensive understanding of the spin and charge ordering in this system.
