If you only have a hull and are not sure about what to add to complete the boat then it might be a good first step to buy a commercially built boat and perhaps modify that to suit. You will see what is there and learn some of the in's and outs. It is not so much that it is super hard to put together a boat from the parts - just that it helps to know what components go with what to make it all work (and to avoid spending more than you need to - or less). I am not well prepared to offer advice on individual components for an electric - has been 25 years since I built my last electric and I am sure that advice is long out dated.
Hopefully someone might chime in with a reputable parts supplier for a project of your scale.