Hi and welcome to ATP!!!
How big are your Cypress trees? If they are over 4 feet tall you can help the Leyland Cypress grow a bit faster by feeding the bajeebers out of them. Get some of that granular stuff, work it into the soil and water - use a little over half what they recommend per tree. Do this every 2 weeks and the operative word here is WATER. Water them every day if possible unless they are growing in a normally moist area.
Your vine idea is a good one .. a really fast growing dense vine is Loofa, Luffa acutangula - the same plant loofah sponges are made of .. they produce pretty yellow flowers.
