The first thing I have to say is ... how the hell can a wood elf team have any chance of doing something good with less than 7 or 8 Fan Factor (in fact, how could ANY team?). Their players are the most expensive ones and the FF are DAMN SLOW to earn ... seriously, I don't get it.
Now, about putting catchers in my roster ... well, my line-elves are already superior catchers than most of the other teams' ones, especially in a strenght-oriented league as mine, so it's not that important to have them early on, they'll mostly be replacement for my dead/injuried/retired line-elves. Early on, they would mostly eat SPP that I would give to my line-elves while the other teams are too slow to make it more difficult. Obviously, they'll be helpful, but I'm able to wait some time. (and seriously, putting these expensive player on the LoS ... are you mad?

Finally, about the further purchases, I've read all your suggestions and I've thought about it a little.
First : for some obvious reasons, apothecary.
Second : to ensure my control over the game in both offence and defence, second wardancer.
Third : depending of my actual needs, a treeman if it's playing too rough, a thrower if most of my line-elves earned their "pass" SPP and a catcher in any other case.
Fourth : third reroll without hesitation
Fifth and further : depending on my needs
Again, thanks for your advices, feel free to argue with my positions.