1. I have a lot of experience with discord's API, since I've been making discord bots for more than 3 years with lots of features and other API integrations, and I've made many twitter apps and bots that include discord bots that monitor twitter accounts timeline for new tweets in real time, desktop applications that automate twitter tasks like following/unfollowing, auto messaging, auto tweeting from schedules and many other features...
2. Not sure, will need to know more details about the project to tell if there's a plugin that might help.
3. Based on the details you provided (and I'm sure there's a lot more details you could have mentioned), it shouldn't take more than a few days.