Beginner gardener - what's wrong with my plants?

[Cinquefoil]

I recently came back from overseas and have discovered my plants aren't looking too good. I'm trying to get into gardening and fix up the garden a bit, but I'm a complete beginner so I'm not sure what's wrong with the plants. Googling hasn't proven too useful as I'm not sure what the proper names of the plants are.

Background: I live in Sydney, Australia, where it's winter at the moment (average temps 10-20c/~50-70F). Most of the plants have rarely/never been fertilised.

Plant #1, a succulent (?) - turning red and leaves look damaged:

Plant #2, not sure of name - also damaged:

Plant #3, another succulent (?) - actually mostly okay, but the lower leaves are damaged. And is the stem meant to turn from brown to green?

Plant #4, yukka (?) - looks like it's slowly giving up on life (so could probably be the mascot of my garden):

Plant #5, lilly-pilly (?) - leaves looks damaged and it has quite a few dead twigs/small branches which I've started pruning off:

Thanks for any help!

[purpleinopp]

#1 = Jade (Crassula ovata.) Looks like some older, mechanical damage to some leaves, but a nice, heathy plant.

#2 = Portulacaria afra. Not sure why it has those spots.

#3 = Aeonium, maybe.

#4 = Agree, Yucca. Looks normal to me...?

#5 = a mystery to me too.

[imafan26]

Most of the plants look ok but need a little tlc. The edges of the jade are red from the sun. The holes and pock marks in the leaves are usually from snails or slugs so you may need to put out some slug bait.

Lily pilly is an Australian common name for shrubs mostly eugenia but could be others. It is some kind of shrub. It needs some pruning. Cut out the dead wood and stray branches. Do not prune anything by more than 1/3. Taking off one or two branches and stepping back or stopping is better. You can always come back to do more but you can't fix it if you take off too much. Do not cut the leader and make a clean cut with pruners just above a node.

[HoneyBerry]

I think that your plants would benefit from being repotted. I did that for my friend's sick plant and it did wonders. The plant perked up and is now thriving, seems happy. The dirt gets stale after a while and the roots can become root bound. If you want the plant to grow larger than it is, you need to step up the pot size. If you want the plant to stay the same size, you might need to trim the roots when you replace the dirt, if the plant is root bound. You should have good results if you replace the soil and use high quality potting soil. It might be worth investing in some clay pots and stepping up the size if the pots. They are better than plastic pots because they breathe. Always be careful when you handle the roots and don't leave the roots out of the dirt for very long. Some plants are more sensitive to having their roots disturbed than others. Some plants respond positively to having their roots trimmed and fluffed. Potted plants sometimes become root bound. If that is the case, it will be obvious when you replace the dirt.