no, they don't know anything except where it came from and where it's going, it's wrapped in encryption on each hop between the nodes in the payment, yes, timing attacks are feasible, if you control a lot of points in the network, same as can be said for low latency traffic over tor

yes the amounts are known by each point along the path, this is why more complex routing including split and join paths and this would also help for redundancy so you can have payments race to their endpoint

there is an inherent vulnerability in low latency traffic, but at the same time the greater the traffic volume grows the less useful the data can be

you don't solve the privacy problem by sticking to 15 year old tech

i am not extremely hostile to monero evangelists for nothing, they are like mormons knocking at the door that nobody is benefiting from their presence