1. Which trader captures more pips?
Both capture the same, 200 pips.
2. Which trader pays more in spread costs (assuming both use the same fixed spread br0ker)?
Both pay the same spreads, 2 times.
3. Which trader pays more in swap, if 5pm EST occurs between B and C (assuming the br0ker makes money by paying the trader less swap on carry-trade-directional trades than he charges on opposite-direction trades)?
Trader X pays the difference between payment and earned interest.
Trader Y doesn't pay interest.
4. How does trader X benefit, profit-wise, from his hedge?
Trader X does not benefit from his hedge, he loses the swap difference.
In fact, if after closing his first buy, trader Y sells at B and close at C, he pays 1 more spread and the full swap cost, but he would make 20 pips more than trader X.
Both capture the same, 200 pips.
2. Which trader pays more in spread costs (assuming both use the same fixed spread br0ker)?
Both pay the same spreads, 2 times.
3. Which trader pays more in swap, if 5pm EST occurs between B and C (assuming the br0ker makes money by paying the trader less swap on carry-trade-directional trades than he charges on opposite-direction trades)?
Trader X pays the difference between payment and earned interest.
Trader Y doesn't pay interest.
4. How does trader X benefit, profit-wise, from his hedge?
Trader X does not benefit from his hedge, he loses the swap difference.
In fact, if after closing his first buy, trader Y sells at B and close at C, he pays 1 more spread and the full swap cost, but he would make 20 pips more than trader X.