I suspect zone 6 is a little harsh for this plant. In Portland (Oregon), the bush will drop all it's leaves if the winter low is 18 or 20 degrees for a couple of days. The defoliation is complete by February. My plant has always re-leafed, re-bloomed, and fruited after such winters. Will have to wait for single-digit temperatures to find out more. This year's harvest is currently at its peak. There is definitely a continuum of habit here: California harvest is long gone by now; mine is at peak, and further north or lower zone, bloom is iffy and fruit is rare, judging by quite a few forum postings over the years. I am curious what counselling zone 6 nurseries are giving for buyers of this plant.

Could be a Catch-22 here, will the plants fruit poorly from repeated repottings or fruit poorly because they are seedlings, even in the ground? It is a hard call. An extended stay in a larger container could be successful, or maybe not. At the current rate of growth, your plants could be hard to transplant in 5-10 years. I certainly would not have attempted to do mine at years 10-15. Although my plant has always been sprawling, most plants I have seen in PDX are much denser and have acute branch angles. And mine might be sprawly because it is essentially a foundation plant, plastered against the side of the house, no morning sun. These plants have many fine, fibrous, shallow roots, similar to rhododendron. If kept potted, I would locate them where the plant is largely in sun and the container is largely in shade during warm/hot weather and leave enough pot headroom for a coarse mulch layer providing additional surface root shading and moisture retention.

If they are from different seeds, they will pollinate each other. They should be grown in separate pots because the stronger one may choke out the other one. Even though they are from the same plant, genetically they are slightly different and so that's why seedlings can pollinate each other. Exact clones (cuttings) are 100% genetically the same so there would be pollination issues. I say different seeds because some plants (I'm not sure if pineapple guava is one) are polyembryonic - many embryos / seedlings from the same seed (Blue Lilly Pilly is an example of poly embryonic-seeds) Think of this as identical twins (poly-embryonic) and fraternal twins (seeds from the same plant) The other seedling may survive - pot it up separate and see. No harm in trying.

I don't really know what the temperatures are in the area, as I don't currently live there. I do know it's in the southern most part of New Jersey (the very tip) and the gardening zone is 7b. Would I have to do anything to protect the plant? If so, what would this involve? All the temps listed are in Farenheit. The place I'd like to grow the pineapple guava (if possible) is in Cape May. I know it'll be warmer in comparison to other parts of the state as result of being located on the coast. Here is a list of temperatures (the averages and the lows). I know the temps will vary from the list but it gives you an idea... Average temps... Jan 46.3 Feb 44.3 March 51 April 60 May 70.3 June 79.4 July 84.5 August 83.4 Sept. 77.8 Oct. 67.1 Nov. 56.9 Dec. 46.8 Low temps... Jan 27.9 Feb 29.2 Mar 35.2 April 43.8 May 52.7 June 62.5 July 67.7 Aug 66.8 Sept 60 Oct 49 Nov 41 Dec 31 Also supposedly (again not sure cause I don't live here currently) the springs are cooler due to the area being in a coastal area.