Hello! The lists of models look cool and interesting to play with. Anyway...
For the Skaven I would recommend defiantly using the Doomwheel as they are really hard to take down and fun to play as they have that annoying tendacy of going out of control and shooting or running over your own units
.Clanrats are great as tar pits for units like the Swordmasters, but I think Rat Ogres are a bit too underpowered for the amount of points as they can be picked of quite easily especially by Bolt Throwers.
BSB great. Warlord great. Screaming Bell almost a definite in every game as it can have some very amusing effects on the game and gives loads of benefits to your army.
For the High Elves the Bolt Throwers are great for the reason I mentioned above (taking out monsters) and Seaguard are great for being able to shoot at the enemy then attack them with their spears up close. Swordmasters great for wiping out big units. Prince on Griffin? Debatable. He is a lot of points for one dude but is quite powerful so... And lastly Mages are great for weakening units before the infantry come in.
As for how to expand the two forces I would buy: Skaven- The Hell Pit Abomimation and maybe a Verminking/VerminLord (or even Thanquol and Boneripper for a very powerful boost) and High Elves- A Flamespyre Phoenix (fun to fly over other units and burn them
) and Phoenix Guard as they are one of the strongest units in Warhammer Fantasy (although if the Skaven player gets Thanquol and Boneripper, Tyroon might be a good choice).
Well, I hope you find this post useful and, welcome!