  Dynamical masses of young planets aged between 10 and 200 Myr detected in
imaging play a crucial role in shaping models of giant planet formation.
Regrettably, only a few such objects possess these characteristics.
Furthermore, the evolutionary pattern of young sub-stellar companions in
near-infrared colour-magnitude diagrams might diverge from free-floating
objects, possibly due to differing formation processes. The recent
identification of a giant planet around AF Lep, part of the beta Pic moving
group (BPMG), encouraged us to re-examine these points. We considered updated
dynamical masses and luminosities for the sub-stellar objects in the BPMG. In
addition, we compared the properties of sub-stellar companions and
free-floating objects in the BPMG and other young associations remapping the
positions of the objects in the colour-magnitude diagram into a
dustiness-temperature plane. We found that cold-start evolutionary models do
not reproduce the mass-luminosity relation for sub-stellar companions in the
BPMG. This aligns rather closely with predictions from 'hot start' scenarios
and is consistent with recent planet formation models. We obtain rather good
agreement with masses from photometry and the remapping approach compared to
actual dynamical masses. We also found a strong suggestion that the
near-infrared colour-magnitude diagram for young companions is different from
that of free-floating objects belonging to the same young associations. If
confirmed by further data, this last result would imply that cloud settling -
which likely causes the transition between L and T spectral type - occurs at a
lower effective temperature in young companions than in free-floating objects.
This might tentatively be explained with a different chemical composition.
