Answer: I've had really good results with Sluggo (Iron Phosphate) bait for snails and slugs so you might give that a try. You can also set up traps. Simply invert a terra cotta pot upside down in your garden and prop it up with a 2-3" rock. When the terra cotta gets wet and stays moist all night, slugs find it an irresistable hiding place. Since they feed at night, they'll look for a comfortable place to spend the day - the terra cotta pot seems perfect; cool, moist and dark. In the morning you simply pick up the pot, scrape the slugs out (into the trash) and replace the trap. Repeat daily. Eventually you'll get control of those pesky slugs.
Rabbits might be deterred with baits (Deer Repellent works but must be reapplied often), or excluded with barriers. If fencing is out of the question, try making cages of chicken wire for your plants.
As for caterpillars, the botanical Bt (Bacillus Thuringensis) is very effective. It acts as a stomach poison so the caterpillars must continue to eat for a while after they have ingested it. (By the way, caterpillars could be the larvae of butterflies as well as moths so don't use Bt if you're actively trying to attract butterflies to your garden.)
Best wishes with your landscape!
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