OSPF routing

I've question about OSPF routing.
There are 3 core switch with layer 2,3 & 4 function
All switch are connecting each other for redunduncy
Each switch are using OSPF as routing protocol

There are also 12 distribution switch with layer 2 & 3
The layout just show 2 of them
The switches also using OSPF as routing protocol

Each distribution switch are connected with 5 to 8 access switch
All the access switch is layer 2 switch
Every switch have their own vlan

Question

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1)If 1 core switch failure, which routing will the distribution route to?
2)Every distribution switch have 3 link to core switches with 1 Gigabit speed. What is the total speed from distribution to core? Is it 1Gbps or 3Gbps?
3)If each distribution switch do the routing it self (not at the core), is it possible to create vlan2 at vlan1? That mean i want to create vlan at distribution switch 1 at distribution switch 2.
4)For redunduncy protocol at core switch, what is your suggestion? can i use VRRP for the three core switch?

Hope my explanation can make u understand.

Core1

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>ip address 172.19.250.46 255.255.255.252
Distribution1

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>ip address 172.19.250.45 255.255.255.252

Core2

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>ip address 172.19.250.42 255.255.255.252
Distribution1

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>ip address 172.19.250.41 255.255.255.252

Core3

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>ip address 172.19.250.38 255.255.255.252
Distribution1

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>ip address 172.19.250.37 255.255.255.252


Question

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1)For OSPF config, we should have 2 interface, is it?
2)Is it possible to create vlan1 at distribution2 switch? i try to ping vlan1 gateway from distribution2 but fail