No you cannot spoil a baby especially if the baby is under 1 year old.
However if you constantly pick up your baby at every cry then they may not get used to crying it out and falling asleep on their own.
So while you should pick up the baby and check on them as needed you don't have to pick up the baby every time they cry.
You can check their diaper, feed them etc all while in the crib laying down.
But if you do want to hold your baby it's okay to do so because they will not be that small for very long and you'll miss holding them in your arms.
Within just 2 years the baby will be too big to really hold in your arms.
No you cannot hold your toddler too much.
You should hold your toddler as much as possible because the toddler years do not last long and you'll miss holding them.
Most toddlers when they reach the toddler age and are up and running around do not like to be held as much though but when a toddler is tired or just wants to relax they will usually like to snuggle up with mommy or daddy or want to sit in your lap and be held and hugged.
You should hold your toddler or allow your toddler to sit in your lap as often as you can because they need the love and affection.
I miss holding my kids but luckily I still have a 2 year old boy who loves to be held as well.
I'm also in no rush to potty train him either because for now he's my last kid and I missed changing those diapers of my other kids.