That is a pretty big tree for just being in the ground for 3 months. The tree is just getting over the shock of being put in the ground. Fruit and leaf drop is pretty common after transplant. It would have been prudent to cut the tree back some and remove the fruit for the first year. At this point you need to provide enough food for the small root system to support all that greenery. You need to provide plenty of fertilizer and water the first year because the root system has not fully acclimated to your ground. An orchardist told me this spring that he gives his newer trees a higher doses of nitrogen because of our sandy soil. Nutrients like nitrogen get washed out quickly. Trace mineral deficiency is common in Florida, so do periodic foliar spraying. I doubt that it is greening on such a new tree. Commercially produced citrus trees in this state are required to be treated with a systemic insecticide to prevent psylid infestation. There should have been a tag on the tree when you got it with the treatment information. A great page of pictures of all the things that your tree is subject too - http://idtools.org/id/citrus/diseases/gallery.php?page=1 Some oil in the winter and a few treatments of copper spray is a good Idea.

do you mean the first set of seedling leaves turned yellow? if so, thats normal, your plants are fine. don't just put them in the garden. you need to harden them off a bit first

We have a couple rose bushes that when the red new growth changes it stays a lighter yellowish green color awhile before changing to darker green... If the leaves do not change to a darker green in a reasonable amount of time than yes something else is wrong...

Those are haworthia cooperi, the so-called "window haworthias". They are usually quite easy to grow although in their native environment, they like to grow partly submerged in soil. They pup prolifically and those pups tend to stick out, dry up and detach from the parent plant and then get rolled around a bit and if they come to rest in a suitable environment, they put out roots. (I'll post some pictures tomorrow, it's 10 pm here and I'm not inclined to go poking around in the garden) When leaves dry and desiccate, they do turn reddish and that's a sign that they may need more water but yours look good and turgid. They tolerate summer rainfall grown outside here and grow happily winter and summer so long as the light and temperatures are conducive. The quickest way to kill them is to put them in blazing sun all day - these grow in cracks and crevices or under bushes and they handle lots of rain, or none at all. Cooperis get squishy leaves quite easily because they are very soft skinned and it's not necessarily of concern, unless it spreads but the angles those leaves are at could also just be the start of pups. Some illustrations. The light is poor, I used a flash, but you'll see what I mean This one is H. Cooperi Truncata. No pups, the leaves are all the same colour This is H. Cooperi Pilifera. There's a small amount of dessication at the edges as I got it in the mail about 2 months ago and it was left to form roots before mailing. It has plumped up considerably since being planted. Probably the same as what you have This is a hybrid "Grey Ghost", it's variegated and looks like it has some H Retusa in it. Notice the darker pup peeking out at the left and the flower starting. Pups can start as a darker single leaf at an odd angle. I'm growing these indoors for the moment because I got them as slightly shriveled plants with washed roots, no soil, in the mail. I'm giving them a chance to develop new roots and plump out a bit before I start hardening them to outdoor life. They are in large plastic pots, plain soil from an area that is geologically similar to their native habitat and I've been watering them every few days. Once they go outdoors, It will be either under a bush or next to the house, where they only get a bit of morning sun and dappled shade the rest of the day. You kill them in summer by exposing them to too much sun, regardless of the whether they are watered or not. I'll post some pictures of the outdoor Cooperi tomorrow