Welcome to Leofinance and Hive!
Many good people here came for the money and stayed for the vibes 😃
But at the end of the day it is both. It goes faster, if you invest some LEOs, though.
Yes, the likes we do call "upvotes" (you can also downvote, but is is done very rarely and only for a good reason like spam, not just for not agreeing with a content).
The RC issue can be fixed by powering up (=staking) some Hive, e.g. 50 would do. Once staked it takes 13 weeks to power all of them down again (1/13 every week). This is also a good way to protect your Hives, as no hacker can grab your Hives, when staked!
Some of the tags you mentioned are from tribes, they have some extra tokens that can be earned, this can get a little complicated. E.g. if you add #leofinance as tag to your post, after seven days you will get author rewards in Hive and in LEO (if the people who are upvoting you have stakes in both Hive and LEO). Half of the rewards go to the writer, the other half to the upvoters.
Most importantly, the more you have staked, the higher your own upvote value is and the more you profit from upvoting others. E.g. I earn more with upvoting (called "curation") than with writing.
This is a huge ecosystem you were entering, full of possibilities...