We have studied (Tb\(_{1-x}\)La\(_x\))\(_2\)Mo\(_2\)O\(_7\) pyrochlores by neutron diffraction and \(\mu\)SR at ambient and under applied pressure. Substitution of Tb for La expands the lattice and induces a change from a spin-glass like state ({\itshape x}=0) to a non collinear ferromagnet ({\itshape x}=0.2). In the ferromagnetic structure, the Tb moments orient close to their local anisotropy axis as for an ordered spin ice, while the Mo moments orient close to the net moment. The \(\mu\)SR dynamical relaxation rate shows a cusp-like peak at the Curie temperature T\(_C\) and a broad anomaly at T\(^\star\)$<\(T\)_C$, suggesting a second transition of local or dynamical nature. Under pressure, the long range order breaks down and a spin glass-like state is recovered. The whole set of data provide a microscopic picture of the spin correlations and fluctuations in the region of the ferromagnetic-spin glass threshold.