Epi's are easy to winter over inside. Just make sure they don't get too much water. The lychee tree will be a bit more difficult. You need more humidity and light. I winter most of my tropicals over in a greenhouse and also use HID grow light systems. The lychee will likely drop foliage when moved indoors. As long as it's kept alive thru the winter it will rebound when it's moved back outside next spring. The only bug issues I've ever had with epi's is scale and it's pretty easy to remove by hand. The lychee is susecptible to more sucking insects, especially spider mites. Keeping the humidity up will help discourage them.

"How do they look to you? Any comments?" Those questions would be easier to answer if you post some pictures. Just sayin'. I brought my SuperDwarf Novak Banana plant in last winter, and I kept it in a room at 75-80F in the daytime hours and 62ish at night using two electric heaters. My "daytime" heater is on the timer with the grow lights. This setup works well to extend the growing season for my Ginger plants. Last winter was my first winter in for the banana plant, and I had just transplanted it from a small nursery pot to a 20 inch planter pot (with about 3 cubic feet/22 gallons of growing mix), so I really didn't expect it to flower. I have all my "tropical plants" under LED grow lights 12 hours a day. The Ginger plants always blossom under the red/blue (3 red:1 blue) LED grow lights. Everyone tells me ginger rarely blooms, but almost all of mine bloom every year. The red light is supposed to stimulate blooming. Maybe this year, the banana plant will bloom as well. I have three pups on the banana plant when I set it out for the summer, and I plan to separate those later this week when I bring everything in and put each pup in its own 3 gallon nursery bucket for the winter. Two more tiny pups have developed in the past month or so, but I plan to leave those on the main plant because I don't think they are big enough to survive on their own yet. Even if you have some kind of insulated "greenhouse" enclosure, you might get better results (blooming/fruiting) if you supplement winter sunlight with pure red "bloom" lights, or 3:1 or even 4:1 red:blue "grow lights" on a 12 hour timer. If it's for a single plant, use 2 or 3 of the focused "spot light" type, like the PAR-38 size from ABI (available on Amamzon).

I'm selling some seedlings online check them out: http://www.ebay.it/sch/nearestheaven/m.html?_nkw=&_armrs=1&_ipg=&_from=

Here is a site that may give you some ideas. http://www.builditsolar.com/Projects/Sunspace/sunspaces.htm#Greenhouse%20Plans If you build your own I would suggest either aluminum or galvanized steel for long life. This is a link to one of the major suppliers of galvanized steel to the industry. http://www.atc-mechanical.com/applications/greenhouse-structures/ Many of us on here have built our own greenhouses. It may take some digging on here but it is well worth your time for the ideas you can get. Your heat source is also something to consider from the beginning. I have radiant heat in my concrete floor which is heated by circulating hot water through Pex tubing in the floor (you would need a circulating fan to make this effective). The heat source is an on demand hot water heater using propane fuel. You might consider some version of a Modine heater fired by natural gas or propane. With a Modine the heat would be circulated with a fan that is part of the unit. Some people use wood stoves or pellet stoves. Good luck with your project !