  We report on the magnetic and electrical properties of a (Mn$_3$Sn)$_2$
triangular network kagome structured high quality Ho substituted ErMn$_6$Sn$_6$
single-crystal sample by magneto-transport measurements.
Er$_{0.5}$Ho$_{0.5}$Mn$_6$Sn$_6$ orders antiferromagnetically at N\'{e}el
temperature $T_\mathrm{N} \sim$ 350 K followed by a ferrimagnetic (FiM)
transition at $T_\mathrm{C} \sim$ 114 K and spin-orientation transition at
$T_\mathrm{t} \sim$ 20 K. The field-manifestations of these magnetic phases in
the \textit{ab}-basal plane and along the \textit{c}-axis are illustrated
through temperature-field \textit{T-H} phase diagrams. In
\textit{H}$\parallel$\textit{c}, narrow hysteresis between spin reorientation
and field-induced FiM phases below $T_\mathrm{t}$, enhanced/strengthened FiM
phase below $T_\mathrm{C}$ and stemming of FiM phase out of strongly coexisting
AFM and FiM phases below $T_\mathrm{N}$ through a non-meta-magnetic transition
are confirmed to arise from strong R-Mn sublattices interaction. In contrast,
\textit{H}$\parallel$\textit{ab}-plane, between $T_\mathrm{N}$ and
$T_\mathrm{C}$, individually contributing R-Mn sublattices with weak
antiferromagnetic interactions undergo a field-induced spin-flop
quasi-metamagnetic transition to FiM state. The temperature dependent
electrical resistivity suggests metallic nature with Fermi liquid behavior at
low temperatures. Essentially, the current study stimulates interest to
investigate the magnetic and electrical properties of mixed rare-earth layered
kagome magnetic metals for possible novel and exotic behavior.
