ergo for small newborn?

[woollysocksaresexy]

I am expecting DC3 shortly, and am thinking about transport options for the kids and how I will juggle my current two DC with the baby. I am not a massive fan of slings but they do come in very handy sometimes, so I am a bit resigned to them! I have two, a caboo which I never particularly got on with and an ergo which I loved (both were v comfy though). I would rather use the ergo if possible as I will probably also be carrying DC2 at times and this could do both. I don't currently have an infant insert but would obviously get one. Just a few questions, though.
Is the ergo actually any good for tiny babies (both my DC have been born small and stayed that way), or does it just feel like wearing a massive puffy thing with a tiny baby inside it which you don't actually have much contact with?
Can you just pop the infant insert in and out or is it rather more complicated that that?
What is the minimum weight for the ergo?
Can you feed in the ergo? Can you feed in the caboo? Not something I ever managed with the other babies, but one can but hope!
Would I be able to carry DC1 safely in the ergo? She will be just 4 and around 13kg, but I'm just not sure if its safe for her.
I can't drive and I don't really want to be carrying around multiple slings and just find the ergo so much easier, but not sure if its realistic.
Thanks for any advice!

I carry my 13.5kg 3 year old in the ergo from time to time.
I didn't get on with the ergo newborn insert, I found it as you described. DD didn't seem happy either. She was large with good head control but was at least 12-14 weeks before the ergo was a good bet.
I was able to feed in the caboo, and the ergo without insert (the latter easily and often!) but didn't try with the insert.
Could you get to a sling library?

I used my ergo from birth for 5lb 15oz ds2, purely because I already had one for ds1.

I could feed in it no problem and used it until ds2 was around 3.5yo

My baby was a decent size but was short, and was too small for the ergo even with the infant insert. We had a rolled-up blanket inside the insert she sort of sat on and that sort of worked, but it was a lot of sweaty faff tbh.

(I mean, weight-wise she was fine for it at nearly 9lbs but shape-wise was short and fat not unlike her mother )

I found the boba 4g brilliant with a new born and would be ok for occasionally carrying your 4 year old.

Thanks all, some really useful comments here!