Is Kraken BTC user wallet a BitGo instant type for withdrawals from Kraken, so that when the transaction gets into blockchain and the recipient is a BitGo instant type wallet address it will need 0 confirmations?
Yes we offer this service but it's an option you have to select in your account. Here are the directions for making deposits and withdrawals with BitGo Instant:
How to make instant withdrawals Go to Funding > Withdrawal > Bitcoin and select BitGo Instant.
Add the address you want to send to (it must be an address from your BitGo wallet or from a BitGo Instant partner).
Select the address, enter the amount, and send! (Note that we charge a fee of ฿0.0005 + 0.1% for this service, which just covers our costs in providing it.)
How to make instant depositsGo to Funding > Deposit > Bitcoin and generate a new address (old addresses beginning with the number 3 can also be used).
Send your deposit to this address from any wallet that supports BitGo Instant (from a BitGo wallet or from a BitGo Instant partner). You will need to select the transfer as a BitGo Instant transfer before you send - if it is sent as a regular transaction, you will have to wait for the usual 6 confirmations before the funds are available for trading).