If tub volume isn't shown, check product literature or ask a salesperson. Then choose a washer large enough to handle your average load without packing it too tightly. But if you wash a load or two every day, you can probably get by with less capacity. Today's washers can be expected to last about 12 years. So include any planned increase in family size in your decision.
Cycles refer to the amount of time the clothes spend agitating.
If your wardrobe includes lots of hand-washables, this cycle is probably worthwhile. A few high-end models offer four speeds. All additional cycle selections are variations of regular, gentle and permanent press. That depends on what you wash. Different water levels also add flexibility by letting you tailor water use to load size.