I have a seedling that I consider very good, so good that when it had to move I tried my best to save it for another location. So far, so good. It's very late and has fruit pulp which is more transparent than many and does not brown when cut open. So don't discount seedlings. The fruit may not be as large as some of the named cultivars, but size is not everything :-) You can train a feijoa to be a tree or keep as a multi-trunk "shrub". Your choice, although some seem to have their own idea of how to grow. As for pollination, many are at least partly self-fruitful but pollen is not very mobile so the wind is not much help and bees are not much interested in the flowers, although I have seen them visit them when a small tree was parked next to a field of wild flowers in bloom. For years my seedling bloomed but never gave me fruit. Then I found the video linked below. It made me laugh, but I tried it and voila! Now I do the pollinating every year, just to be sure. Here is a link that might be useful: Hand-pollinating feijoa with the paintbrush

Guava trees/shrubs in general do not produce much fruit for the first 3 to 4 years. It is perfectly normal for the flowers to drop off during their early years of growth. Guavas like full sun. If they are planted close to other trees, they will not produce fruit due to the shading. Guavas are fertilizer hogs but do not produce well with lawn fertilizer= too much nitrogen. I tried to copy a chart to give you an idea of how much fertilizer Guavas like but the copy did not translate well. Refer to the link below for a better look. Tables Table 2. Cultural practices for producing guava in the home landscape. Operation Jan Feb March April May June July Aug Sept Oct Nov Dec General1 Apply NPK Apply NPK Apply NPK Apply NPK Nutritional sprays2 Apply micronutrients Apply micronutrients Apply micronutrients Apply micronutrients Iron applications3 Apply iron Apply iron Apply iron Watering Water trees during dry periods, every 7 to 10 days and 1 time per week during flowering and fruit development. Insect control Monitor for Caribbean fruit fly, mites, and moth larvae. Bag young fruit and monitor for leaf pests year-round. Disease control Monitor for red alga and anthracnose. Apply copper along with nutritional sprays or apply alone once or twice especially during the wet season (May to October). Pruning4 Prune to reduce tree size and open up the canopy. 1, NPK, nitrogen-phosphate-potash. Dry fertilizer mix which includes nitrogen, phosphate, potash, and magnesium. Apply fertilizer 1 time during early fruit development and at the end of harvest. 2, Nutritional sprays are most effective during the warm parts of the year. See text for makeup of nutritional sprays. 3, Iron applications are most effective during the warm parts of the year. 4, Pruning may be done anytime during the year to control tree size and induce off-season fruit production. Severe pruning should be avoided during November through February to avoid possible damage due to freezing temperatures. Here is a link that might be useful: Guava Growing in the Florida Home Landscape

Most Pineapple Guava's, 'Feijoa sellowiana' are self fertile and do not need a pollinator, although it would help. Do you have a named variety? If so, it should bear fruit when it reaches maturity in a few more years, probably 2 or 3. Al

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.