I also felt very nervous about feeling invaded postpartum when I was pregnant but I had to just make sure I was communicating properly with my DH and he told me he'd support whatever I wanted (and did). My MIL is very helpful but she was basically saying she'd come and stay for at least a week after the baby was born, do night shifts etc. Amazing help and so kind of her but it wasn't what I wanted - I planned to breastfeed and knew she didn't approve, fundamentally as lovely as she is she's not my mum or someone I grew up with. I felt really uncomfortable at the idea of needing to be awake and presentable and emotionally together if she was living with us. She was also coming in with a key while I was pregnant which didn't help. I'd lost my own DM to suicide just over a year before I gave birth so subject was touchy. And there were points that MIL has always been pushy on, well-meaning but I was used to always trying to act very respectful and that jarred with me now being the mum and wanting my choices respected.
Anyway we ended up having PIL to visit the day after our DS was born in the evening. Then I went to a birth centre for aftercare and breastfeeding support so didn't come home until about 4 days after the birth anyway, in the evening. DH's auntie came a couple days after that, then BIL and family came from London the next day (weekend). I'm also from London, in a city where DH grew up and most of my remaining family and friends are in London. My DB and best friend didn't come up until 3 and 4 weeks pp. We had other visitors in between. Saw ILs every week.
I'd read that lemon sized blood clot essay about how messy pp is and was worried but it wasn't like that. Yes I was tired when we had visitors (DS cluster feeding insanely);but I mostly had a good time. I struggled more with DH's older family as DS was basically taken off me as soon as they walked in and lots of jokes/comments about him not needing to feed when he got hungry and I needed to take him back. A lot of it was about me needing to gain confidence and better communication skills as a parent though, now I'd have no issue saying to hand him back - and I'd be less anxious handing him over knowing I could take him back when I wanted too. I've chilled out a lot in general just with time parenting.
I'd say: 1. Wait and see how you feel pp 2. Don't communicate any hard "rules" to visitors in advance, just schedule visits when you're all able to and don't make a big deal of delaying them 3. If you end up breastfeeding, try and make visits happen in the afternoon if possible. I could barely get functional for noon in those days having been up basically all night for weeks, morning was when I could catch up on sleep somewhat 4. Do have you or DH remind anyone holding the baby "no kisses please" assuming that's your rule. You'd be surprised the random people that think it's fine to kiss a baby on the face before its jabs. Our relatives were great but we still did remind them and I'd be firmer about this if we have another, it was not worth the stress.
Oh and feel free to give a rough guide of time for visits and keep them short and sweet, you can also say I'm just going to have a lie down if someone's visiting - or you can take baby with you after they've met and had a cuddle and say LO needs to feed or needs a change/sleep. I did struggle to sleep while anyone was over though.
And PP while yes you are bleeding and usually covered in fluids, it wasn't as extreme as I'd read in that respect.