  We examine light diphoton signals from extended Higgs sectors possessing
(approximate) fermiophobia with Standard Model (SM) fermions as well as
custodial symmetry. This class of Higgs sectors can be realized in various
beyond the SM scenarios and is able to evade many experimental limits, even at
light masses, which are otherwise strongly constraining. Below the $WW$
threshold, the most robust probes of the neutral component are di and
multi-photon searches. Utilizing the dominant Drell-Yan Higgs pair production
mechanism and combining it with updated LHC diphoton data, we derive robust
upper bounds on the allowed branching ratio for masses between $45 - 160$ GeV.
Furthermore, masses $\lesssim 110$ GeV are ruled out if the coupling to photons
is dominated by $W$ boson loops. We then examine two simple ways to evade these
bounds via cancellations between different loop contributions or by introducing
decays into an invisible sector. This also opens up the possibility of future
LHC diphoton signals from a light hidden Higgs sector. As explicit
realizations, we consider the Georgi-Machacek (GM) and Supersymmetric GM (SGM)
models which contain custodial (degenerate) Higgs bosons with suppressed
couplings to SM fermions and, in the SGM model, a (neutralino) LSP. We also
breifly examine the recent $\sim 3\sigma$ CMS diphoton excess at $\sim 95$ GeV.
