The rest of the ability resolves, as even if one effect fails you can still resolve the rest of the ability since the one does not hinge upon the other
#Glyph Overlay and Reaping Blade
mortal pelican
5.3.2b Second, each of the resolution abilities of the layer generates its effects in the order specified
(except go again). If the parameters of any effect are undetermined, those parameters are determined
before the effect is generated (see Rule 1.8.5). If an effect fails, any remaining effects continue to be
generated (Rule 1.8.8). If the layer no longer exists after the generation of an effect, the last known
information of the layer is used to determine the remainder of the resolution abilities and the effects
that are generated (see Rule 1.2.5).
steady belfry
If the life gain was required, it would say "if you do" rather than "then"