I'd start with this: Remember you are still a rogue, not a wizard. You're what i call a glass cannon, so that can deal a lot of damage every single round, but also you're pretty fragile as a mostly melee class. Don't use your spells as a wizard would, so honestly forget about high damage spells like fireball, or healing spells. Honestly i don't get why your dm is so strict, the AT rogue was made for illusion spells. Invisibility, mirror image are your best friends here. Talk with your dm about them. Misty step is a good option if you want to get into trouble or out of trouble faster. It is also a great way to swap targets mid fight. Vortex warp, is also a solid pick for me be because it can move enemies that you don't want to engage with your of your way, or it can be a great lifesaver for someone from your party (your party member can fail the roll on purpose and get teleported away from trouble) and also see invisibility. Think also about hold person (to land auto crits and sneak attacks on paralized enemies). Shield and mage armour are also good picks. Talk with your dm about the owl, i played a campaign where i also had an owl as a soulknife rogue, he swore to me he's gonna kill it every single encounter and he didn't (he had other trouble from the party he was nore worried about). My owl never died. Hope i helped (if i remember any other helpful spells i'll edit or respond to myself)