Lychee plants are very delicate and grow very slowly, especially when they are small. I belive the 5-1-1 mix is very fast draining and you should check the soil moisture level before every watering for a few weeks so that you can determine when to water. Unlike many other fruit trees, Lychees actually like the soil a "little" moist but never waterlogged. If you 5-1-1 mix is fast draining, you may need to water a little more often but check the soil before you water.

Do not add any fertilizer to your lychee trees untill they have become established in their containers or in the ground for at least 2-3 months. After about 2 months, you can give it some organic fertilizers such as Fish/Kelp emulsion. I have killed several of my lychee trees by giving it chemical fertilizers so please learn from my mistakes.

You should put up a wind barrier because lychee leaves are very sensitive to the wind. Lycheesonline.com has a lot of good information on growning Lychees. Good luck with your lychee trees!
Simon