Is it possible to trade pre-market via TradeGate?

Your existing TBSZ provider may ask you to provide IBKR's bank routing information for cash deposits  in order to proceed with you transfer. 

IBKR will show you the bank routing information once you submit the TBSZ transfer requests in Client Portal:…

IBKR Lite clients will not be able to select SMART routing for orders in US stocks outside of the Overnight; such orders will be routed through Lite where possible.

For all other orders entered by an IBKR Lite client SMART will need to be selected when available since direct routing of an order is not supported…

Advisors have the ability to trade mutual funds on behalf of their clients by using either an allocation order or by direct allocating…

No, you cannot direct route an order to a specific market maker…