Hello if i play Primary Target against scum with max figure cost 6 - eClawdite - BT-1 - eSentry droids Deploy cost 10 (figure 5), which target am i eligible to target first?

Find the highest figure cost of hostile figures, then if the figure has that cost, it is eligible. (I.e. all figures tied in the largest figure cost are eligible.)

For the figures you list, BT-1 and Clawdite Shapeshifter would be eligible.