So lets say in the Bitcoin network (I guess you are more familiar with that than with LTC) there hasn't been any block minted in 30 minutes, the current block is 468359 and everyone is mining block 468360. They have all been mining for 30 minutes but then I broadcast a high fee transaction (900 satoshi/Byte) and my transaction gets included in block 468360. 1. How does that work? 2. After I broadcast my transaction do they all start their mining over?

How does then for example viaBTC's transaction accelerator works? I know they change the order of transactions (include) before the block is found but still, wouldn't that mean that after they add a new transaction they would have to start their work over?

(Not how it works but) Let's say viaBTC finds a block but still want to include one more transaction into that same block, can they do it? 1. Would the block still be valid after that? 2. Would it be a very miniscule thing to do? 3. Or would they have start the whole mining of that block again and it would take them the same time that it takes to mine any other block. (hope I'm not asking the same question)

Hello, let's say that I'm a solo LTC miner and I mine an LTC block. After I find a block I decide not to publish it, can I include/exclude transactions from that block before I broadcast it?