In reply to NorthernGrit:
Any metal gear will be fine, so krabs and wires.
Quickdraws will probably want new slings/dogbones so would be best sold as just a set of krabs for someone to sort themselves.
Slings should probably not be re-sold.
Cams - this depends on the brand; if you let us know the make/model we can help. Cams with captive loops for slings to go through can be perfectly safely DIY'd. Others with cable loops may need to be repaired by the manufacturer but plenty of them offer this service (although for some manufacturers the convenience/cost could be greatly improved on).
If the textiles are dyneema and have been barely used and stored safely (no chemicals, direct light exposure, etc.) then there is no real reason they would be unsafe. People have done break-tests on dyneema which was this sort of age or older but had not been used/barely used and it was still failing above MBS. If a cam is rated for ~14kn and the sling is good then it will almost certainly still achieve this (as a loop of sewn dyneema is usually rated >20kn by itself).