@Mary Johnson - hi Mary, I looked up your location, if you are in Texas City, Texas, along the coast, near Houston, you are in an area where the climate is almost frost free. They will make great patio trees, grow them outdoors. Grow these seedlings on, step them up into larger pots until they are big enough to go into a large nursery can, say into large 20 gallon pots. Set the pots on their own dollies - small platform with wheels - before you fill the pots with media. They will be heavy. During the few weeks when weather is cold, you can wheel them into a garage, or other area to protect them from cold. Then back outside as soon as it has warmed up a bit.
The litchi is likely fully winter hardy in your area. You can go for a 4 or 5 foot tall bonsai. At this size the large leaves won't be much of an issue.
Same for the Mango, except when nights dip below 40 F you will want to bring it in. Actually of the 3, mango will likely make the better ''bonsai''. Again, you are looking toward a 4 or 5 foot tall tree, smaller, you won't get much fruit, if any. While mangos are hardy to 33 F or 34 F, cold below 40 F is very likely to kill flower buds, so wheel it indoors when temps are predicted below 40 F at night.
Jack fruit is a thermophile, I've only heard of it being grown in areas where the lowest temps are above 50 F. Indonesia and Malaysia are its ''home'' climates. Parts of Thailand are too cold for it. This one will need to spend much of winter indoors. Given its size, a big plant, I don't know how practical this could be.
Pomegranate and citrus are likely fully winter hardy in your area, they would be good patio choices. Sapodilla is also winter hardy in your area. Maybe even the guava family including Eugenia, the bush cherries. Jaboticaba is not winter hardy. Lots of good fruit trees you could use for patio bonsai that are better choices, but you already have the 3, so why not?
From seed, there will be little or no bonsai technique needed other than keep them growing for the first couple years. Get them big and bushy, then they get cut back to bonsai size.
Keep us posted, and take pictures and post them.