Can Solo 401k's have an automatic enrollment feature?

I believe that you should be able to set up a solo 401k just as you would any other 401k but wanted to make sure that the automatic enrollment feature was available and that then you could also receive the government tax credit for this?

Sure you can have auto enrollment if your plan document allows it. No, you can't take the start up credit for a 401k plan where the only participant is the owner - see Code Section 45E(d)(1)(B):

(B) Plan must have at least 1 participant 

Such term shall not include any expense in connection with a plan that does not have at least 1 employee eligible to participate who is not a highly compensated employee.

While WCC’s explanation of the tax credit make this point needless:

If a plan is not ERISA-governed (because, for example, there is no employee beyond an owner or deemed owner), unpreempted State law (for example, a wage-payment law) might preclude an automatic-contribution arrangement.

While the start-up credit isn’t available, the automatic enrollment credit is in IRC 45T and it does not include the requirement that the plan cover at least one NHCE.