1. The only way to expedite the process at all would be time travel: playing multiple in-game days at a time. But even then you're going to have to find ways to earn bells: turnips (Reddit, in particular, seems to be reliable for finding good prices), island beetle hunting, or perfect fruit orchards. Other people can help you out with fossils and art for your museum but the bugs and fish you have to catch yourself.
Don't feel you have to grind though. That's a great way to burn yourself out on this game. If you want to catch some fish and donate them, good. But you shouldn't necessarily feel like you need to catch six months of fish in a short period of time.
2. We just had a whole slew of events from Halloween through New Years. Isabelle will be sending everyone a gift on Valentine's Day but other than that, it's just the monthly fishing tournament until Festivale. Thonky has a
calendar of events you can check out. They also have a bunch of other information worth looking through.
3. We can help you out with that here. I'm certainly willing to help with catalog ordering. You can either ask here or PM me directly with what you need.
(That goes for any of our newer members: if you want something, just ask.)
Besides possibly glancing at some of the past OTs which had more of the basic info still in the first post, asking us questions like this is probably the best thing you can do. The core group of posters here have been playing pretty much since launch and are always willing to help with information or in-game stuff.