Either the brown or the sweet peet seem best to me. They will both slowly break down and enrich the soil Good soil makes good roses!
Alfalfa pellets can be toss around on the ground but they take much longer to dissolve and feed the soil than the tea does But maybe over the winter would be a good time to let that happen.
Since you've buried the grafts you only need to mulch up maybe 6 or 8 inches. Even then sometimes mulch can cause canker on the canes because it holds a lot of moisture against them. It's a tough call. You take a chance of winter kill or canker. Take your pick.
If you have a VERY dry winter it is advisable to water if you can. Dehydration and desiccation are some of the main causes of winter kill. Sometimes more than the cold.
