Live in Vietnam ( visa informations)

It depends you. TRC(3 year) is convenient for some, for some a VEC(5 year) and for others a 1 month/3 months/1 year visa.
Use the search function on the top to learn more about a spousal TRC and VEC.
Advantages and disadvantages were discussed in each topic.

They are getting rather lengthy and sometimes stray off course but you should read these two thread pinned at the top of the forum.

https://www.expat.com/forum/viewtopic.php?id=541937https://www.expat.com/forum/viewtopic.php?id=369913

I believe that your home registration is for temporary residence only.  Half of HCMC has the same status as their permanent residence is registered in their hometown.  Your husband should be able to sponsor you for both the VEC and TRC but I am not sure if he needs a permanent residence registration or not.

If you really intend to work for your husband's company then you will need a work permit anyway but if not then getting the new TRC through your husband would be a lot cleaner.  Also if your husband switched jobs, you could be left scrambling around with no visa status.  A work related residency card goes away if the related work permit is cancelled.

I have a VEC but plan to switch to the TRC when we return to live.  It is slightly more expensive but a lot easier than the VEC with only one renewal every three years instead of every 6 months.

Your VEC will only be renewed for 3 months once your 6 month stamp  upon entering Viet Nam has expired. There was talk of a 12 month stamp, but as usual it was just talk. Time to actually get rid of the stamping system altogether.

As you mentioned, TRC - if you get, will be based on Work Permit. Without Work Permit, foreigner is not entitled to work and reside in Vietnam except the case he/ she is investor having business in Vietnam.  Accordingly, you can contribute  a small capital to your friend's company or of anyone you can trust. The legal procedure is not complicated and in fact, no government agencies come to your company to check about capital contribution schedule.

And one more thing, not all consulting companies provide bad services. ^^