Code edits on live Magento site needed

This Magento site has been heavily modified, with some core files being edited (not ideal, but it has been inherited like that).

There are some code changes needed:
1. Remove To and From from the "Add message" functionality on multiple address checkout

2. Add ShareThis functionality in top right next to facebook/twitter icons (needs to work on secure site)

3. Invoice alignment/font layour changes - client prints orders on specific labelled paper, so needs to match layout correctly.
A. Address and Message need to go down 1 line (currently cut off top left hand corner on label)
B. Quantities ordered needs to be shown next to item.
C. Font size for Order Details needs to be 12 minimum (currently 8 and difficult to read). By this I mean the products that have been ordered.
D. Order and Invoice number still come onto the label, move these down by 2 lines in addition to the 1 they will come down when number 1 is done.
E. Is the custom field 'Do Not Open Until' date appearing? If not, it needs to be shown
F. The phone number should not be on the address
Original file that it needs to match: http://ge.tt/3zCUpeJ/v/0?c

4. Sort out the multiple shipping addresses double payment problem
cycle of payment, orphaned orders. http://screenr.com/uWZ8

5. Text on Add A Message on both single AND multiple address checkout is too feint, needs to be black - http://i.imgur.com/jcaPy.png

6. Edit wording on single AND multiple address checkout for billing AND shipping addresses - http://i.imgur.com/2OQGZ.png?1
- On dropdown, "New Address" should be "Enter A New Address" - can it be bold?
- On wording before dropdown, "address book" and "enter a new address" should be bold
- Can "enter a new address" in wording before dropdown be clicked to automatically select "enter a new address" in dropdown and display new address fields.

Site URL in Clarification Board, or ask me!