The orcs look ok.
I would possibly drop the giant for more troops and another hero as big monsters tend to be a waste of points at sub 2000 points.
High elves list over runs by 110 points.
Heavy cav rule this game if the board does not have enough scenery and linear obstacles.
So bear this in mind on your selection.
The eagles are very useful for mopping up enemy artillery and causing command penalties.
I would potentially drop a unit of archers and 1 unit of reavers and take a bolt thrower.
That said, I always pick fluffy lists and take loads of archers even though shooting is not usually a game winner

The empire list is bang on the nose points wise.
A lot of players do not rate skirmishers as they do not add to your break point (essential part of the game) I would swap them for a helblaster (same points) to protect your cannon from attack.
But all this is just my opinion.
Get what you propose and see how it plays (amending the orc list so it is legal

)
Then use those findings for expanding them to 2000 points.
I always buy max of the min-max levels and a significant number of the none limited choices. So for a 2k list I normally buy around 3k of models. This gives me a very nice choice when it comes to picking a force and the fact that I never play the same list twice. But friends of mine are still playing the same dwarf list they picked when the game was released

A good start for all 3 armies may be the battle of the five armies box set.
It will definitely cover off your goblin needs whilst giving you a few of infantry units for the high elves and empire. anything leftover you can either keep or trade.
As for painting, once you start you will find it very easy.
There are some decent hints and pointers on these forums along with the painters tale to help keep you motivated.
The toughest thing about this game is finding opponents and I wish you good luck with that

Cheers
Mick