London, Paris, Rome, Venice, Munich

[TravelKid]

Hey! I'm taking a 3 week trip in May and it's looking pricey to stay...partly since I"m looking to stay in the major places: London, Paris, Rome, Venice, and Munich.
Whats the feedback on:
(London) St Christopher's Village
(Paris) Square Caulaincourt, Absolute Paris
(Rome) Via Carlo Cattaneo or I've heard suggested on here : The Friendship Place, The Beehive Hostel, M&J place Hostel
(Venice).....I"m lost, I don't know anything about it and can't find a lot of suggestions....
(Munich) Easy Palace, Wombats City Hostel, or Pension frank

Any help would be great!!