Re #1, by running the wire alt to battery you should not have to run one to starter relay. But by running wire to the correct terminal on the starter relay you would not need to run additional wire to the battery.
Agreed. There really isn't a good way to add a wire at the battery terminal that I've seen, especially where you'll need to go by/across the battery ground terminal and other possible short circuit to ground points.
We suggest going to the starter relay because there is a lug there suitable for properly securing a eyelet terminal. Routing a minimal length wire, taking the shortest path over the top front of the engine is foolish too. Any wire added anywhere should be routed well away of heat and sharps. Best route is following the OEM harness. You'll un-tape and re-tape or better yet, invest in wire loom.
