If its easy you're looking for I'd go with the pitmaster 110. Not that I don't see a lot of value in the Stoker or the Guru but I'm a fan of the simplicity of the IQ 110. Just an opinion.
I use the IQ 110. It's perfect for me. It doesn't have the features of the Guru or the stoker but for me its simple and bullet proof. If I was going to get into competitions I'd most certainly look hard at those two but for now I'm extremely happy with it.
I've done lots of belly but never in a WSM. My best results have come from 2 stage method. Google Gordon Ramsays pork belly. His method can be simply modified for the WSM.
Any blade type coffee grinder. More than 25 bucks is overspending. A mortar is good to have on hand for some tasks but general spice grinding with it is to much work IMO.
If use use a non-sausage ground meat though I'd put it through a stand mixer for a while. If you look at home sausage making books they all have a period of mixing the sausage for a time not just to incorporate spicing but to develop proteins similar to the way kneading bread develops gluten...