Ok so I remember there being a Metal Coat in the Team Spirit city,(I already forgot the name,lol). I think one of the dumpsters you check on a certain tile has a Metal Coat and there might even be somewhere else too. There is also a special way you have to evolve the scyther while it holds the Metal Coat. I'll say it has to do with the eccentric lady in Clover town.
Looking it up, friendship levels are just "happiness" levels in the debug menu. As far as I know there is no in game way of checking your happiness levels. You see that in the debug menu by going to the pokemon screen and there should be an option for debug when you choose a certain pokemon, underneath the happiness option. It will let you choose the level you want them to be at, but it will also tell you your current level too.
You get happiness by leveling, walking 128 steps and sleeping with your pokemon i'm not sure if it's every time you sleep with them, or after they cum each time during a sex session,(might even work for the female pokemon too, even though they don't have a sex animation).