Here is a photo showing where a coil retaining clip goes in the front left...
My jeep came from the factory without any retaining clip for the coils. And the jeep years when they did include them, they only put them on the left side. The reason they only put them on the left is that on the right (passenger side front) the clip retaining position is located where the base of the coil is on more of an upward turn... and so that passenger side clip often pops out from the coil spring pressure over time.
Anyway, if you want to buy front coil spring retainer clips you can google for them. I see that Rustys sell them. Kindof a ripoff at $10 for what they are but seems most places are charging the same. But your issue isn't really with the front coils falling out so you would probably be fine without front coil retainer clips until you get a more flexy front suspension.
Rustys Offroad: Coils - Heavy Duty Coil Spring Retainer Clip
For the back coils, jeeps never came from the factory with any coil retainers. They are meant to be held in place because (a) the rear doesn't usually flex as much as the front because of the rear sway bar... and (b) they are kept in because of the rear bump stops, which of course your jeep doesn't have.
Yeah, I suspect the previous owner purchased the coil spring spacers without getting them with extended rear bump stops. Coil spacers are often sold alone without the bump stop extensions. And so, when the previous owner installed them they discovered that the factory bump stops would not fit with the new coil spacers and they just continued on with the install and not doing anything about the rear bump stops.
Your probably missing the front rubber bump stops from the cups because they couldn't push them back into the cups after installing the front spacers (using wet soapy water helps get them back into the cups)
*edit: Stu's website shows how you can create your own rear coil retainers:
http://www.stu-offroad.com/suspension/retainer/retainer-1.htm
But I think you'd be fine if you just had rear bump stop extensions and rear bump stop. You'll have to get hold of the rear bump stop cups too since those are missing.
so your shopping list should be:
- a pair of rear bump stop extensions:
http://www.roughcountry.com/jeep_xtras_1093.html
- a pair of rear bump stop cups: junk yard rear tj cups... or zj front cups will also fit on rear of a tj.
- a pair of rear bump stops: get these also from junk yard or google it because I'm lazy and hungry now. ha

Have fun!