LOL.  Welcome to cat ownership.

- The "site" you are on is gathering data from a "newsgroup" and
rebroadcasting it.  You should be aware of that, read the fine print there.

- you need a place for your cat to do the claw stretching and sharpening
thing which is approved for that.  Get or make a cat tree covered in carpet
and encourage your cat to use it

- that said, cats will do a certain amount of damage to stuff and cause wear
and tear no matter what you do.  Figure out how to deal with it.  (They are
much better than kids... in that respect.  At least cats never show up at 2
am in the back of a cop car.)

- close your latpop lid when you are not using it

- cats will get on your counter no matter what you do.  Either clean them
before you use them or just get used to it. Nobody has ever died because a
cat walked on the counter. Your 2 year old is probably collecting more germs
and random feces smears than the cat ever will so relax about that.

- Xmas tree?  Well... that probably can't be helped much.  Get a squirt
bottle for "correction", it won't hurt them and may help them learn what not
to do.  Use soft ornaments on the bottom, or just hang the cat toys up there
as ornaments.  After all, the tree is for the entire family to enjoy, is
your cat not part of the family?

You are not playing with the cat as much as it needs.  (They vary in
peronalities that way)  Get toys that get them involved in running around to
burn extra energy.  Maybe switch to low-calorie food too.  I use a laser
pointer and get all four of mine racing around for 15 minutes at a time.
They are MUCH more mellow after you let them burn off some steam.

Having more than one cat will definately give them an outlet.  They will
either play with one another, or just get social contact more often and will
quite often calm down a bunch. Plus, they respond better to you going away
for the weekend if there are two or more. Also, just a few years of age they
calm down. 2 year old cats are like teenagers, they have a lot of energy and
not much sense.