Wow nice stats. That helps a lot not have to worry about ASIs so much. I would personally stick with Tome as it's most versatile IMO and you can still get a regular familiar with it. Having a super familiar is very nice, but I don't think it's worth an entire subclass selection as it has little to no other features. Blade would be great at later levels as you would get to add your Str AND Char to damage at Warlock 12, but again, it's pretty limited, and it doesn't make you much better at all until Warlock 12. No point in Shillelagh with 18 Str.