LEGO's are made of ABS. So it would seem to make sense to start with that but.....
Printing small ABS parts with good layer adhesion can be a challenge along with dimensional stability due to shrinking and warping.
so it might be a bit of a challange. Also, dependent on the brand, can be high fumes, and some think ABS fumes to be toxic.
PLA may be to brittle for what your doing, but is much easier to print with and has better layer adhesion, low warping, and low srinkage, it has less and perhaps more pleasant fumes, and most think the fumes non toxic or at least less toxic due to it being make of natural starches...
I saved the last for what id try first... I would try PETG which has better layer adhesion then ABS, low shrinkage, high dimensional stability, low warping, and can withstand a lot of abuse, and exhibits no fumes. but.. is more flexible then ABS and takes a bit more time to get your printer dialed in to print it well. Also, it seems that even changing colors within a brand of PETG may require different settings to get it just right.
if your worried about fumes, then PETG gives you no fumes.
I always operate the printer with ventilation in the room none the less.
i used to print a lot with ABS, but i have changed out printing PETG for most cases where id use ABS. there are some good threads on PETG here, but id start wth the mother of all petg threads
viewtopic.php?f=11&t=1615&hilit=petg. ESUN is the forum favorite supplier of PETG, and if you want to go that route, will be the brand most can help you with here.
. Is there a rule of thumb how much PLA (PETG) shrinks or you just need to play with it until it works ?