= Solution
Write $L_i$ for the <lithium> $2s$ orbital at site $i$ and $N_i$ for the <sodium> $3s$ orbital. Reading the printed axes, the lithium coordinates have signs $1=(-,+,+)$, $2=(+,-,+)$, $3=(+,+,-)$ and $4=(-,-,-)$; the sodium sites are $5=(+,+,+)$, $6=(-,-,+)$, $7=(-,+,-)$ and $8=(+,-,-)$. The normalized <tetrahedral s-orbital symmetry combinations> are
$$
\begin{array}{c|c|c}
&\mathrm{Li}&\mathrm{Na}\\ \hline
A_1&(L_1+L_2+L_3+L_4)/2&(N_5+N_6+N_7+N_8)/2\\
T_{2x}&(-L_1+L_2+L_3-L_4)/2&(N_5-N_6-N_7+N_8)/2\\
T_{2y}&(L_1-L_2+L_3-L_4)/2&(N_5-N_6+N_7-N_8)/2\\
T_{2z}&(L_1+L_2-L_3-L_4)/2&(N_5+N_6-N_7-N_8)/2
\end{array}
$$
Each $T_2$ row takes its signs from the corresponding coordinate, so the three functions transform together like $(x,y,z)$. These coefficient vectors are <orthonormal> when intersite <orbital overlap> is neglected. A common sign reversal of any row is physically immaterial.
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