You absolutely need some sort of thermal compound between the cob and heatsink. The pads are cheap, easy, and clean. You could use thermal paste instead, but it’s neither easy or clean. Either work, they ensure good thermal contact between the cob and sink.
The wago 412 should have taps for 2 wires, the 413 3 wires. If you didn’t catch on, the 415 has taps for 5 wires. The first 3 numbers are the type of wago is 221, they are fine. You will want 2 of the 412 for connecting driver to cord for receptacle (1 for hot, and another for neutral. Then 2 more of the 412 for connecting the driver output to the led’s (1 for DC positive, and another for DC negative. That’s a total of 4 of the 412. However if and when you go to build your 2nd light, you could swap 2 of them for the 413. That would allow you to run both drivers from 1 plug. Or not, if 2 plugs is better for you. Due to relatively low cost, this is one thing I would suggest to buy extra of. They are handy to have around the garage even if you don’t tinker much. They have a few assortments available on amazon if you shop there, they’re also available at menards and I believe home depot if you have access to either.