Enclosure Items
Feeding & watering troughs and play equipment can make you a lot of points. If you have four zebras in a pen, that's 24 points x 4 = 96 points to feed them; a feeding trough doubles that, for 192 points per feeding. Enclosure items get more valuable the more animals you have. If there's only one animal in your pen, you'd be better off getting another animal than getting all three enclosure items. (It'll be exactly the same, points-wise.) But if you have three animals, now you're talking about doubling all three of them - much more valuable.
If there are both carnivore and herbivore feeding troughs available, it doesn't actually matter which you get for which animals. Go ahead, put hay in the lion exhibit, they don't mind.
Breeding stations and habitats help tremendously for breeding - in fact, without them you will find breeding too frustrating to bother with. They add 5% (watering hole) and 10% (habitation) to your chances, raising you from "Not likely" to "Sometimes". (Your chances will end up being in the realm of 1 in 3. In the love zoo it'll go up close to 50/50!)
Re. charging the things, don't buy charges - not worth it. Sometimes you'll get one in cards, or there might be like double charge weeks, so go ahead at that point if you have diamonds to spare. Charge up the items with your highest-scoring animals. Not the items in your largest pens!