As I understand it (based on the info the anaesthetists give the women who deliver in our hospital) an epidural will not increase the risk of an EMCS however they do come with a slightly elevated risk of needing an instrumental delivery.
With regards to opiate analgesics in my spiel I explain that they won't take the pain away entirely the way an epidural will (if it works correctly). However what it will do (for many women not all) is put you in that state where you've had a few drinks and you stub your toe and without a drink in you you'd be hopping all over the room crying, but because you're a bit drunk you're aware it hurts, but it's tolerable, you're removed a bit from the pain.
I also explain that it can make you feel sick but to counteract that we will also give an anti-emetic but we can't reverse the effects of the drug once you have had it.
I then explain the effects it has on the baby, I explain the sleepiness, dopiness etc you might feel and how it has a similar effect on baby and how due to this we try and avoid giving it to close to delivery as sometimes the babies are slow to notice they have been born and can require resuscitation. As that sometimes scares women I explain that there are always babies that catch us out and come sooner than expected so there are lots of measures we can use if a baby is born very affected, we just try and avoid it if we can as it can be quite scary for parents.
I explain doseage (we generally use diamorphine) and how there are 2 different amounts 5mg and 10mg and the amount of time we can leave between doses (3 hours for 10mg) and the maximum does I as a midwife can prescribe (20mg).
Opiates aren't for everyone but do your research and come to a decision that works for you. Good luck!