cordon trees

Hi all, I mentioned in allotment thread, i want to grow lots of fruit, I do have a cordon red gala apple oin apot at home( though hasn't flowered this year, did last though mini apples dropped, wasn't worried as it's first year, surprised no blossom, what have I done wrong? ) thinking of getting more, should we go for cordons, to either put in ground or in pots, or dwarf and try stepovers/ espaliers? would like apples, pears, cherries and plums,oh dear I really am so clueless all advice very much appreciated