Combining Aspects is not possible - would have liked to know

Just a quick heads up, yesterday i failed two beastcrafts I was looking forward too and gathering for for quite a time. Nothing that turns me away from the league, i'm having lots of fun, but it was something i would have liked to have known before my mind went loose with possibilities for the weekend.

1) Aspect mods on amulets are mutually exclusive - i'm running aspect of the crab which i crafted onto an amulet with space for a second aspect. Made sure i had my tree right for when i got it, and waited with my second Fenumus til i was leveled up cause the first destroyed me (six times). Alas after a great fight it turned out the whole idea of two aspects at the same time wasn't possible.
I can imagine it somewhat to make the sets feel more like sets, but at the same time, traditional sets aren't what GGG wanted with them, and indeed i'm having fun with a single piece. By that logic though i would see no harm in people trying to combine different parts of different sets - should be a good poe-style feature. Maybe there's some other reason, but it would have been nice knowing it wasnt an option anyway.

2) Remove a Prefix add a Suffix doesnt work on as an Annul on items that are full - I had a Stygian Vise beastcraft lying around for the second i'd find another Fenumal Scorpion, which would be an upgrade if i manage to remove one its prefixes for a WED roll. It was full with suffixes but i gathered "whatever", as i didnt need another suffix, i just wanted the prefix freed up. Alas here too, when i finally got the scorpion to have a go at this, it turned out impossible because the item had no room for mods. Would have been nice to know this wasnt gonna fly, i would have continued crafting on the belt earlier.

All in all i'm having a great time in bestiary ssf btw, make no mistake! Lots of other bases that i have been playing around with since the patch that upgraded the rare recipes, and SST feels like a nice deep skill in the ways you can approach it. Just wanted to share some possible QoL! (if its possible.. sounds a bit complicated, otoh player expectations turning out differently can be a real bummer sometimes)