The top picture is from Buccaneer and rest are from F4 FGR2. There's not any sealing mechanism between the joints, so these can’t be fuel or hydraulic related. They might have something to do with the blown air slaps/flaps systems, I'm not sure.
Yes they are engine bleed ducts, either for anti-icing purposes, or for blowing along the flap leading edge to improve the efficiency of the flap.
High temp ducts often depend on just a smooth metal flange that mates with its connecting duct to provide an adequate seal, with possibly some compression preload provided by the springyness of the duct when they are butted together. They don't have to be 100% air tight, just tight enough.
According to the following cutaway of the Buccaneer, 53 and 67 seem to be good candidates for your answer i.e. ducts for the leading edge, aileron and flaps blowing system.
According to this other cutaway, the only system located in the outer wings of the F-4 is 78 and 123 i.e. the slat actuators.
Manage to find this document, unfortunately don't have the full access. https://arc.aiaa.org/doi/pdf/10.2514/6.2018-0561