完了 means finished, 完全 means completely (filling all requiremenrs) and is used as an adjective or adverb (so you can say 完全に完了), 完成 refers to doing something to completion - less about something being over (完了) and more it being completed, often physically.
期待 expects good things - it expresses hope. 予想 is just a prediction/guess based on your data. I don’t have a ton of experience wirh 先回り but it’s “anticipation’ seems to be more about doing something before someone else, which is a use of the English word ‘anticipate’ that we don’t actually use super often.
用意 支度 are just identical though >_>