Crozet's connections quest "kill elite lab monsters" takes the longest of all other quests, including those obtained later in the game like Furious. I have been playing the game for nearly four months and just finished his connections requirements a few weeks ago. I have never wasted lab tokens. You could technically 'farm' a lab stage with specific pathing that allowed you to maximize your elite monster kills, but at most this is like 4-5 elites per token, and hurts progress to raid, etc.

Expecting new players to wait 3 months before they can reliably farm W11 is not good advice, and I see people confused in the daily question thread all the time (as was I when I was given that advice).

Taranor Royal Guard is the only (current) f2p ice tank for W11, unless you include A Momo due to having Tamarinne (if you have Angelica, she should be tanking, not A Momo).

Crozet, Rose, Krau, Angelica (with A Momo) and Tywin are all 'upgrades' to Taranor Royal Guard that should be used in his place when summoned. Special shout out to G Purrgis if you have the stats to make him work, as well.