I presume that you mean set blocks? Zendikar Block has 6 Planeswalkers Lorwyn Block has 5 Planeswalkers Alara Block has 5 Planeswalkers M10 has 5 Planeswalkers (these are reprints of the Lorwyn Planeswalkers) The best planeswalkers are found in Zendikar Block: Gideon Jura, Jace 2.0, Nissa Revane and Sarkhan the Mad
It depends on the card and the circumstances, but in many cases yes. Planeswalkers are always very good.
No.
Rise of the eldrazi
Magic The Gathering - Duels of the Planeswalkers 2014 - 2013 VG was released on: USA: 26 June 2013
no
No, only if you want to play Duels of the Planeswalkers.
Yes, they are treated as permanents, so can be targetted by cards like Vindicate, for example.
Yes, you can have two planeswalkers in play, so long as they do not have the same name or type, otherwise they are subject to the Planeswalker Rule. If you have two planeswalkers with the same name or type both of them most be discarded. You can't have two Planeswalkers with the same 'type', meaning you can't have both Ajani Goldmane and Ajani Vengeant in play - while the two cards have different names, both are 'Planeswalker - Ajani', and would both be destroyed because of it.
No, permanents are cards on the battlefield, ie Enchantments, Artifacts, Creatures and Planeswalkers that have resolved to the field, as well as Token creatures, and Lands.
no, you cannot. you can customize the premade decks with a handful of unlockable cards, but there is no true custom deck building
Chandra Nalaar first appeared in the Lorwyn set book along with the first Planeswalkers to be introduced into MTG including Garruk and Ajani.