I don't think there is a firm answer to your question.

1) I believe motor loss is significant and needs immediate medical intervention. Motor loss occurs with some autoimmune types of PN, and severe types like GBS. IVIG and immune suppressing treatments typically are used. I know someone who had severe GBS and had plasmapheresis to remove the attacking antibodies.

2) When it comes to burning... one needs to understand that there are two types of temperature nerves in the periphery.
Cold sensing and heat sensing. The heat ones seem to go nuts more commonly, and start firing willy nilly in response to diet and other triggers. Using cold stimulating menthol, will block the heat response, for a temporary time period, and give relief of burning.
I find that burning is my main problem. But occasionally I get pain in my feet too. This week, I've been having some GI problems, and of all things, my surgical scar on my left instep, flared up and hurt like mad! It does not do this often. It had been numb for almost 20 yrs after all the nerves were cut to remove that hemangioma which bled every day until then.
Since the nerves have grown back, I get discomfort from many types of shoes now, and like 2 nights ago, the deep pain in that scar. I rubbed magnesium lotion into it, and it was better in 1/2 hr.
Biofreeze was going to be next. But I didn't have to do it. The foot is not swollen either (which it does sometimes).
So I just experiment with things, and discover what works and what does not. I get blank looks from my doctors, and I won't accept that at all!

3) I think tingling happens in two ways. Waking up and going numb. Dr. Oz,(who I don't really like much) used one of his Science fair illustrations once on a show that said tingling was due to minute bubbles in the blood forming when circulation is restored to an affected are that was constricted. Like fizzing, is how he described it. I don't know about THAT. I would like to see proof of that.

4) Nerves in general seem to be very fragile. And we don't know that because we don't have problems usually until the problems come on. We take everything for granted inside us, in a rather naive way. But because nerves are designed to signal the person of danger, warning of things temperature wise or injury wise, they are very sensitive and fragile. Looking at it this way, sort of explains why some people get the symptoms they do. Whatever the trigger is, it must be setting off alarms that the nerves are supposed to pick up. I do think that sometimes they do not "turn off". I saw that with Lidoderms and my MP. Once I got that 15yr old nerve turned off, it stayed off for the most part. It will twinge with application of any kind of heat or over-extension of the leg ..but not like it was before the Lidoderms!