Zone 7 precludes all-year outdoor cultivation - you're going to need frost-free winter conditions for tree ferns, so factor that into your plans and ask yourself if it's realistic to go any further. Dicksonia squarrosa is the more tender of the two species you've plucked out of the air, although it is much faster growing. Its fronds are considerably more compact than D.antarctica, so that might be a consideration if you are contemplating a glasshouse or conservatory where space is inevitably at a premium.

Hardy, fast-growing evergreen tree ferns don't really exist - the quicker species tend to be more sub-tropical, whereas the tougher varieties (it's all relative though) are much slower growing. Winter defoliation is inevitable below Zone 9 or 10. Only under glass is it possible to get what you seem to be asking for, and that still brings with it a host of difficulties relating to summer shading, humidity and ease of watering.

Planting in massive tubs (both for moisture retention and stability) would be the only practical way of approaching outdoor cultivation in a Zone 7 climate, but you'll still need to work out some way of overwintering these barely portable ferns.