1. The dragon eyes are MOSTLY for whales, yes, but if you've played for a while (and in a decent union) it's often quite possible to save up for 1, and use bricks from towers to LB them. It's a lot of time and work, but if you want to push your main team to the next level, that's one way to do it (assuming the dragon eye weapon in question is good and worthwhile).

2. Yes, most of the eye shard rewards are from ranking rewards. If you're an active player try joining a slightly better union, it doesn't have to be top 5 (those require way too much grinding), but top 30-50 is very possible due to the low active player count. Trying to carry a union by yourself when you're not very strong just isn't a good idea.
2a. It's done using paratrains, while strong players can certainly solo up to 400 or so, the scaling becomes pretty insane beyond that, and the boss will just casually 1-shot all your himes if you let them attack at all. So you don't.

3. You just keep grinding away while waiting for the next event to come along. KH is a long term game, you can't really rush it unless you're spending. Use the time to work on some side teams just in case RNG decides that you can make them useful someday. Prepare fire for the wind tower... then wind for the thunder tower 2 months after... etc.