One thing I want to say, which is just my opinion: Don't beat yourself up if you need to take shortcuts in the beginning (well, at any point, really) because many things are "little things" when it comes to raising your children into happy, healthy adults. I really wanted to do everything the same for both kids, but I have come to realize it just isn't going to happen and in some situations, it isn't what is best for the kids. Overall, with my youngest being two now, I'm pretty happy with how well we did the things we wanted, but I'm also happy I was flexible when I needed to be because I would have struggled far more if I wasn't a little flexible.
I'm not saying my compromises are the same compromises you'll want to make, I'm just saying that you should try to remain flexible on things that don't really matter when you're struggling.
I've passed this stage, but my kids are two years apart and here is what I recall from that time:
a) Diapering: I just made it work. My younger child was teensy, too, so cloth diapering was out for a couple of months because I didn't have a stash that would fit and it wasn't worth the investment of new diapers. We used sposies and it helped in a lot of ways - less laundry, just ease of putting them on, etc. I had my older child help with things as much as I could and as much as he wanted - getting a wipe, getting a new diaper, etc.
b) Bedtime and naptime for the toddler: Naptime was a difficult one for us because my baby didn't want to be put down and didn't sleep great. We kept the time(s) the same, but I just held my baby through the naptime ritual (i.e. reading, singing a song, etc.). Oftentimes I had to stand and rock the baby while we did our naptime ritual, which meant DS would get a story from my head rather than an actual book. My Moby wrap was also necessary. For bedtime, DP took over with our toddler, which worked for everyone.
c) Baby napping when toddler wants you: This was another difficult time for us and we just winged it, too. It seems like 90% of the time my toddler wanted me during this time so I just did what I had to do. For a long while I refused to do TV/DVDs, but then I used DVDs (since I could control it) to get us through the rough spots. I hated every minute of it (screen time is one of my "things" and it may not be for you), but it did help, especially since he hadn't seen much of anything up until that point. I probably did this for 2-3 months until we got to some stability. Eventually this got much easier to where my toddler was okay without me (I would leave a fun activity/task for him to do while I was gone, he would play on his own, etc.) and they began napping on similar schedules.
d) Toddler/Baby boundaries: I had to take my baby everywhere. Everywhere. I used a wrap (Moby) and that was my salvation for this, too.
I had a Moby wrap for my first child, purchased on Craigslist, and I just kept it for baby #2. I loved it since my second baby was very, very small. It does have a learning curve, but YouTube has a lot of helpful tutorials. My baby practically lived in this wrap. I did have to be careful because there were only certain holds that felt comfortable and safe, but that also made it easier to master. There may be something easier/better out there now, but I already had it, it was cheap, and it worked.