For trigonal by-pyramidal structure, we know that lone pairs are preferred first to be positioned in the equatorial position. So in SF2Cl2 lone pairs will be positioned in the equatorial position.
After placing lone pairs in the equatorial position, double bonds are then preferred in the equatorial position but as there are no double bonds in the structures we are considering, so we jump on to the next rule i.e. atoms having higher electronegativity is positioned at axial position and atoms having low electronegativity is positioned at equatorial position. You can also interpret this in another way. You can also say that atoms having higher atomic size is positioned in the equatorial plane and atoms having lower atomic size is positioned in the axial plane.
Now coming back to your structures, PF2Cl3 and SF2CL2 we will see structures in this manner:
F is more electronegative than Cl , hence the P-F bonds are going to be shorter than P-Cl bonds and S-F bonds are going to be shorter than S-Cl bonds. As F's (fluorine's) are located in the axial position, hence these P-F or S-F bonds which are actually axial bonds are shorter than that of equatorial bonds (i.e. P-Cl or S-Cl bonds).
In PCl5 all the atoms around P are basically the same i.e. Cl. So the electronegativity factor of Cl doesn't play any role in reasoning out why axial bonds are longer than equatorial bonds in case PCl5. The reason is - in PCl5 the axial bonds suffer repulsion from the equatorial bonds so they become long. The equatorial bonds providing repulsion to axial bonds also happens in case of PF3Cl3 and SF2Cl2 , however this factor is overlooked/ not considered in cases of PF2Cl3 and SF2Cl2 because there this factor/ effect is not dominating. In those cases as the type of atoms attached (i.e. electronegative atoms) are different, hence the effect of bond length shortening due to the electronegative atom attached is the dominating factor.