Question 1

If it stays mild with the weather you can do now, they are very shallow rooting so dig a good space around the shrub NOT close to the stem, mulch with bark but keep a space free around the trunk, and the best side facing out when planting

Question 2

With all this rain we have had I would say no , its just to wet and you will cause more damage than good with all the trampling around you will cause , leave till late March and a good spring feed a week or two later

Gg

It is better to rake or scarify in spring if you were unable to do it the previous autumn - Depending on conditions of weather - My lad has a lawn care business so this is recommended by him not me -- Ken

If the Rhodies have a lot of top growth you could lightly prune them to reduce stress on the roots. Keep them well watered, with rainwater, all next Spring and Summer. Check them after frosty spells in case they have risen out of the ground.

All the comments are really useful, thank you all!