Freeforming can start anytime. You won’t have to restart your locs at all. Manicured-turned-freeform locs won’t ever look like the locs of Valerie June or Ladene Clark, because locs with a round-shaped lower shaft only rarely grow in flat. However, you can develop some bumps and wiggles and keep a full grown crown of hair, like Nerissa Irving.
When you freeform, if a couple of locs constantly stick together at the root, you can choose to let them grow together. Quotidianlight on YouTube did this, and her number of locs decreased by about half. However, if you are happy with the thickness and number of your locs, just separate them regularly to prevent the roots from growing together.
Unfortunately, there really is no magic trick to make thinned hair grow faster. There are some myths and rumors floating around that certain topical treatment will make your hair grow faster, but all are false.
Products don’t really have anything to do with hair growth. Hair growth is primarily a hormonal process, so topical treatments tend not to do much.
The hormones involved with hair growth can change with age, diet, environment, and stress levels.
Oil will help seal moisture into your hair and can make it smell very nice. However, thinning roots is a problem caused by mechanical tension (tight and/or too frequent retwisting or styling) and/or hormones. Freeforming will definitely relax your scalp and allow fragile hairs to grow back. Putting oil on your hair after washes will help keep your hair from getting dry and brittle, ultimately preventing breakage.
Most oils are very comparable in function. I like jojoba oil because it’s light and scentless. But you can choose a scented oil, like coconut or tea tree. Some sources also say Jamaican Black Castor Oil is a good nourishment for damaged hair, as well. Experiment as you go, and you’ll discover what you like best!