1) Use the number format function to force the trailing 0 to display:
to show a decimal as a percentage, multiply it by 100, then concatenate the percentage sign:
<?php echo((0.10*100)."%"); ?>
2) I dont fully understand the question you are asking. If you don't show the standard delivery option in the select list, it wont be able to be used as an option for shipping.
3) use the substr() function: