maybe teamwork feats? i don't know this archetype sucks so bad, just play a master summoner for a truly one man army
(was I right to grave dig, rather than post anew?)
The crafting team seems neat. How does assisting on crafting work? Does EVERY ally/summon who rolls above a DC 10 add +2 to your craft check? So if there were 3 of crafters working near the same work station, could they all be working on 3 different things, and still be able to provide timely assistance to one another (i.e. they all get a +4 from two allies helping out)?
According to the rules, is it true that an eidolon can be skilled in craft, even if it has no hands? For this team, I suppose I'd spend at least 1 evo point on each of the small eidolons to make them skilled (Crafting), and maybe 1 evo point to give the bipeds slam (replacing claws), in order to take most advantage of the natural attack allotments I get.
One idea I had was for small sized serpent eidolons (with reach(Bite), such that at level 3, even before evolution points were considered, a spear wielding brood master and his brood might get 4 attacks of opportunity against enemies as they moved out of threatened zones, OR against a single caster (i.e. by summoning them near an enemy caster as part of an ambush). If the previous Crafter-Team concept could be done with serpents instead of bipeds, then it seems that this "army of AoOs" could be done with my Tinkerer-Team (applying the extra feats to weapon finesse).
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But it seems that the way to min-max the brood master would be to apply a different base-form to the different beasts in your brood. So that'd be what? My personal approach to this topic would be to look at low level eidolon builds, since those are basically what you might be building.
Scout: small quadruped (16 dex) which would be sneaky enough to get in, but also fast enough to get out? 1 evo point stealth. Maybe 1 evo points perception. It wouldn't get the nat armor, but might get the skill points. 1HD might be enough.
Tank: small serpent (AC 16; 18 dex; 2 nat armor) vs. aquatic (which also seems to have a land speed of 20ft?) (AC 16; 14 dex; 4 nat armor).
The aquatic would have a 12 str and a single bite attack, which is perhaps more efficient than the serpent, which would have extra attacks it could not use. 1 evo pt would get it +2 Nat Armor, so that would be (at level 1) 18 AC, which is respectable, even before Mage Armor, and other Nat Armor increases.
So Aquatic would be what I choose for my tank.
other (biped): A biped might be able feed fallen allies heal potions, or other wise retrieve fallen weapons from the battle field. Giving it the "throw anything" feat or the "catch off-guard" feat might make for nice monkey companions who fling poop, or smack people with sticks. It might be worth spending a feat on it, especially if there aren't the extra natural attacks to go around.
I'm not sure how Use Magic Device would work, but at the very least it seems the biped would be able to use a tanglefoot bag. And with an army of crafters at work (discussed above), it may be possible to keep tangle foot bags plentiful.
other (serpent): Serpents may allow the highest touch AC, but I'm not sure what else they'd be good for. What's the point of a melee attack with an 8 str?
One idea might be to give a team of small serpents the basic magic evolution to get some 1/day touch attacks. While this would pretty lame most of the time, it might be a nice moment when 4 of you shoot out 4d3 worth of acid splash against a flatfooted foe.
...yeah, I got nothing. I don't know what you'd make small serpent for, unless it was your scout option.