My gut reaction is that having a single cell is going to simplify things(*) even if it doesn'tbring any efficiency improvement - at the expense of less endurance.(*) no charge balancing needed, fewer mechanical connections, simpler to monitorone cell.
2. Will I run into issues using 14500 cells in parallel to increase my capacity?
3. Will I run into issues using 14500 cells in series? (They have onboard protection circuits)