A brush border also present on the luminal face, greatly increasing the effective surface area.
Chloride ions move with sodium ions.
Water passes from lumen, through PCT, to LIS passively due to osmotic considerations. From here the NaCl solution can either leak back to lumen via 'tight junction' or enter peritubular capillaries. The faster the capillary uptake the less leakback there is. Rate of capillary uptake depends on forces favouring uptake minus forces opposing uptake. Capillary oncotic pressure depends on degree of glomerular filtration.