Standby Replication and Replication Delay

Hi,

so I got two questions:

1) I have multiple Postgresql Standby servers replicating over WAN, and
I would like to reduce that to a single connection.
Is there a utility that can be put in between and store the wal files
from the primary and provide it to the standby server, even if they are
delayed by > 1 day or more (provided there is storage?)

2) These standby servers sometimes run very long queries (2 - 3 hours)
and at some point the replication stops, because I guess some row
version which are used are removed on the master.
I do have hot_standby_feedback "on", why does this still happen,
shouldn't this prevent the removal on the primary and allow replication
to continue even if queries are active?

Thanks
Thomas