Yes, just be careful. They are curious creatures and will try to get into everything. I suggest you don't plant anything harmful to cats, and keep an eye on any interest in catching fish.
Consider placing your pots on a seedling heating mat. This will warm the soil and increase chances of germination. Sow another round if you think you planted your seeds too...
This depends a lot on the cat's personality. Some previously outdoor cats actually prefer to be indoor cats as they feel more secure. The trick is to provide ample opportunity...
A truly feral cat is unlikely to adapt well to an indoor life. A feral cat is uncomfortable with human company and may well feel trapped and be very unhappy....
