I have played a bit of Blood Bowl lately, I would like to express my opinion. (Especially if you are just starting, and you are not.)
Number one; People dont have Blood Bowl teams, they have Blood Bowl collections. Unlike other games the low model count allows you to go to town on just a few miniatures.
The Human Metals are slightly under-rated by the public. I think they could look wonderfull with some TLC and conversions. (The pistolier heads come to mind) Converting plastic kits over can sometimes look goofy, rarely do they look correct next to true fantasy football miniatures.
You need the blood bowl set to play and help host events, its nice to have extra templates as well.
I would combine 1 with 3 or 2 with 3. Use the plastics from blood bowl or the metal team complemented with pistolier bits. Sell the Orc Team to fund your blood bowl exploits or help a new player.
4 is a good option, but not allways for human players. I love Impact Miniatures; the Gnomes play well as Ogres, Dwarfs, Humans or Halflings. Deadlings as Undead, Necromancer, Halflings, exc... They provide a range of options for the price and nearly allways look unique.
Note that the Divine Wind, Spartians and Desert Dogs can be used as a few races including Humans, Highelfs, Dark Elfs, Orcs exc... With some carefull modeling it would not be unthinkable to make a team that crossed such lines with the standard figures and a few conversions.
I guess it all depends on how you want to model and where you draw the line between Warhammer and Blood Bowl.
Anyways my two cents.
Good luck and Nuffle be with you!
Looking at the previous work you have posted (Ogres, Warmachine, Flagies,