If you're going with Fender for this project, then you don't have to worry about neck style. Any neck you can use with a Squier guitar will be bolt-on, so you don't have to worry about jointed necks. On the contrary, if you're modding an Epiphone or a Gibson, you'll want to look into jointed necks. Obtaining a new neck can be difficult. The easiest place to locate authentic Fender necks is off of eBay. You'll find the people who generally sell them are hobbyists or luthiers who have dismantled the original guitar and no longer need the neck. Although, if you don't like dealing with eBay, there are always Picker's Parts. Be aware though, they aren't cheap. Prices range from $100-$500 on individual necks. Necks can be one of the more difficult parts to find. When pickups are brought up, there'll be too many to go through! Just keep an eye out on eBay and other smaller retailers for the type of neck you're looking for. You could also buy a dead guitar and simply salvage the neck if you really can't find what you're looking for. For any Fender or Squier electric guitar, replacing the neck is remarkably simple. You just need to unbolt your current neck and bolt on your new one. You can re-use your old tuners, or you can always pick up a new pair. Squier guitar tuners can often be a little iffy. They're generally one of the things most Squier owners complain about. They aren't too expensive. https://rockinreplicas.com/