I do love a plan!
Don't worry, you're doing just fine.. It's really difficult to interpret things sometimes especially when you're sleep deprived and trying to tackle so many things at once! That's what this site is for... It's amazing!
Anyhoo, let's get started on what I think. I'm sure a moderator will be along soon to help too, but here's my two-pence worth
You need to get rid of that cat nap soon. Trust me... I kept it too long and it results in NW (night wakings) and suchlike. Once you start to increase her A's it'll naturally drop off the end soon anyway.
Short naps of 40/45mins been she's UT (under tired), so I'd work on that first A first. You will need to increase the A time slowly.. Too much too quick results in a OT (overtired) little bubba.. bTDT! Try and stick to a 12-hour day in total. Sometimes we lose sight of that when we're concentrating on each A.
Now some lO's like a short A for their first one and some prefer it to be the longest (mine is the latter). Do you know which one yours is? Either way, I'd add another. 15mins to that first A in the am. You might still get an UT nap, but hold it for a couple of days then increase by another 15mins. It's normally hard those last 15mins as they may give you sleepy cues as they're used to going down at that time. Just do something low-key. I usually carry DD around for those 15 mins and point out things in the house.
Wrt breast feeding. I'm not an expert as I quit at 3months but I do know breast feeding on demand to a degree is fine. You just don't want to fall back into feeding her to sleep. I would feed her on wake up from her nap, you don't have to wait until a specific time. That's the best thing about BW. It's so adaptable. For example my DD has 2 bottles and a solid meal in her first A.. It really doesn't matter as I make sure she has at least 15mins A before I put her to sleep.
I'm sure a moderator will be along soon with more and probably better advice! Xx