Most recipes can be halved or doubled without much problem. Goat's milk is often heated a couple degrees less than cow's milk, so add 2 deg. C to your make temperature and cooking temperatures. I wouldn't add lipase for the first make, in part because I've found it is easy to use too much and throw off the flavour you're trying to get. If you do add some, just add a couple grains so you can say you did!
As for rennet, recipes give amounts which could be way off for you, depending upon the strength of your rennet. I have 3 different rennets that I use, one is super strong, one very weak, and one in the middle. To get 10 Litres of milk to floc in 10-15 minutes, I use 0.6 mls of the strong but about 7.0 mls of the weakest! So as you can see, "1/4 tsp, or 1.25 mls" of either of these is going to be way off. So, use an amount of rennet proportional to what you usually use (i.e. if you normally make 8 Litres and now are making 4, cut your usual rennet amount in half, etc).
Most important, make sure you keep very detailed notes, post them here, with photos!