Just to add my two penneth, my lo was mix fed until 4 months when he wouldn't keep still enough for bf any more so fully ff. I started giving him some purees but two weeks later moved onto finger foods too. It doesn't matter whether they're bf mix or totally ff, it doesn't impact on blw imho.
I've never read anything by AK but by two weeks of spoon feeding my lovely healthy homemade purees the novelty had well and truly worn off and I was bored rigid. Plus the timing is always rubbish, they want to eat while you're eating, or while you're cooking, which means you have to stop everything and start spooning and you never eat a hot uninterrupted meal. And they're still having 3-6 milk feeds a day which you also have to stop everything for. Soon it feels like you do nothing but feed your baby, it's as labour intensive as having a newborn.
He's now 6 months and I'm still giving some purees but I'm moving more towards fingerfoods all the time. I'm working towards him only being spoonfed things which you would naturally eat with a spoon, like porridge and yoghurt etc
They cope unbelievably well with fingerfoods, he has never choked, and only gagged a few times considering the amount he's eaten.
We eat our toast together in the morning, he shares my food if we eat out in a cafe (loves munching on slices of cucumber, tomato or cheese) and the best thing of all is when he's hungry and his bottle isn't quite cool enough, or we're out somewhere, I can just grab a ricecake or something for him to tide him over for a while.
If I'd known how easy it was I probably wouldn't have pureed anything, but he's used to to a greater volume of food now than he can feed himself iyswim, but he's getting better all the time.
The only downside to blw is your own diet needs to be pretty good as you can't feed them off your plate if you happen to be having beefburger and chips. It will make you aware of just how much salty/fatty/processed foods you eat.