Also how much LTC is in a block?
50 LTC / block, each block is generated at 2.5 minute interval, so for 1 day there will be 576 blocks or 28,800 LTC max.
Question is what settings should I use for CPU scrypt miner and in reaper?
CPU mining is kinda pointless now.
For Reaper settings, you can see Vorksholk's guide.
What about port forwarding?http://portforward.com
How can I tell if my computers are solo mining successfully?
Depending on your luck, you'll get block (50 LTC) + transaction fee after a while.