UO Second Age

does str help with completeing a steal? what else helps ?

I'll tell you what helps a steal:

Manning (or womaning) up and doing it somewhere other than WBB.

Just say no to 10hps and a death robe.

Karma

The guards will be keeping a close eye on thee

I never tried enticing an npc when attempting to steal but I know that there is a short span in between peacing where you can hide right in the midst of once aggressive mobs and even players. It may throw them off who knows? There was a time where entice worked at 5 second intervals if I remember correctly I haven't used it in awhile though but I am guessing it's ten because of the huff and puff about stealing and gating pets with it.

(if it does seem to work I would even consider making a scripted bard that targeted specific npcs in your area of thievery)

You would still run the risk of players seeing you but if you kept drawing the npcs towards you I bet your chances would start to increase.

Unless you are making a townie thief I wouldn't recommend putting entice or peace on him however. If you are making a townie I would say do it if it works. It may do the opposite but I am guessing when enticed it is too busy listening to the music to call guards on you. Something to look into.