However I am also slightly aware of programs to roll over into new investments and avoid taxes.

Then you can rollover your current IRA and invest.

I plan to rollover from my employer's 401k to one of the above.

If that's the case, at some point all the assets will be released either for rollover to the new plan or to an IRA A/C.

It can accept contributions and rollovers from other plans in the same fashion as any other IRA, either during the initial setup or in the future.The one thing I would be sure to check on is whether your new 401(k) would let you roll out any of the funds you are rolling in. 

Read this:  https://www.fool.com/investing/general/2015/10/02/...Under certain circumstances, you can roll-over your 401k to a self-directed IRA and buy a rental property from your IRA.1.

You will want to review your plan documents, bu the following solo 401k distributions rules generally apply:After-Tax Contributions and Rollover Contributions.

@Hank HebelIn the case of an IRA that was inherited by a non-spouse beneficiary, as long as the inherited IRA is processed as a direct-rollover (i.e., a direct trustee-to-trustee transaction) it will not trigger the payment of taxes.

Essentially had three 401Ks with different custodians and simply did a “rollover”.Luckily, my laziness paid off as most folks are told to roll it over to the current employer... bad idea unless it’s either mandated or required (usually <5K vested balance per 401K).

Can he/should he simply rollover the SDIRA to a 401(k) so that he can add funds?