1) Yes, LSP packets contains information of the network.
because each node's LSP packet describes their portion of topology and by combining all LSP packets we get the network topology information.
and along with this each node then knows the whole network topology after combining.
note : here they said "LSP packets" not single packet.
We use flooding as a forwarding technique because in our network we have different routers that may be using different topologies so while routing, these different topologies may create inconsistencies, loops or other problems.
This is the reason we use flooding.
3) Yes, they are converted into Tree using Djiktra's algo
because link state routing runs using Djiktra's algo(mainly) and to make routing tables of nodes we have to find the source tree using Djiktra's algorithm.
For each node we made source tree from Djiktra algo and them made routing table for that node. This way we made Routing table of every node using source trees.
Example for pt 3