shrub maintenace

In my new garden, I have several large woody shrubs that I would like to give a severe trim, how far can they be cut down to?
The ones I want to keep are
Variegated Holly about 6ft high - I want it down to about 2 and can it be transplanted?
Heather- unknown type but flowering now about 2ft high but would like it about 6inch high and would like it moved
Rhododendron about 6ft high and very leggy how do I encourage it to get it compact
crocosmia can they be transplanted

Thanks
Dmg

Wern't crocosmia on GW this week. That Klein bird said to dig up corms in March, split them as they grow on top of old corms, throw old ones away and replant the new corms. I shall be trying it this year as mine have had a poor show the last two years. All foliage and no flowers much.