Both these are hardy fruits and so do not need a greenhouse, however having one gives much earlier and much more reliable crops. Just the protection from frosts, rain and birds is immensely valuable, the earliness is a huge bonus.
Apricots and cherries need similar treatment to peaches though preferring cooler drier conditions, a freer draining more limey compost, and plenty of ventilation. It is most advisable to buy modern varieties on dwarfing rootstocks. (It is possible to raise your own fruiting apricot bushes from seed in less than a decade.
Seedling cherries are longer coming into crop, grow too large and do not often produce quality fruit.) The newer apricots such as Tomcot, Goldcot, Flavorcot are heavier cropping and more compact than the traditional Moorpark (which is still very good). Apricots are self fertile so you only need one, however growing two or more ensures better pollination. Cherries are more picky so ideally grow several, or a Morello which will pollinate almost any other. Summer Sun, Cherokee (Lapins), Stella, Sweetheart and Kordia are all reasonably self fertile. As these both stay so compact when grown in tubs it is possible to house a good number in one modest greenhouse.
Planting into the border will give too much growth for most smaller greenhouses, the permanent housing allows pests and diseases to build up and it is hard to give them a winter chill. So grow in tubs moved indoors in late winter to flower and crop and out again for summer and autumn.
Grow cherries and apricots in well drained tubs of soil based potting compost enriched with bone meal and plenty of lime, I prefer crushed seashells. The tubs are kept outdoors until late winter then brought under cover though they do not need come in as early as peaches and the end of February is fine. They then come into flower and leaf very early and benefit from hand pollination as few insects are about- I use a small water colour paint brush for apricots and a feather duster for the more prolific blooms of cherries.
Now whereas peaches under cover like frequent spraying with water it’s better to keep apricots and cherries drier and especially when the latter are in flower as these easily go mouldy. Cherries also need very careful watering as they swell as if their compost ever dries out the fruit will split when rewetted. Liquid feed regularly and lightly until either crop starts to ripen then only water and but lightly. Because they are confined in tubs and on dwarfing rootstocks neither will ever need much pruning other than removing dead or congested shoots. Pests and diseases are also seldom a problem -though unless you put netting over your ventilators blackbirds will find your cherries so be warned. After fruiting is finished the tubs are moved outdoors for summer and the rest of the year.