Just to be clear I don’t work for envato so can’t comment on details regarding their processes.
For what it’s worth you are not the first person to comment on finding it hard to locate the right support details but at the same time in most cases (not all) people have not read the documentation, and from a UX perspective where these are located is probably the best option.
I’m sure envato support are interested in any feedback you want to give. https://help.market.envato.com/hc/en-us/requests/new
On your other questions:
- yes a plugin won’t edit the actual theme. This is going to be the case with any one that you use.
Having two page builders installed is not going to be doing the site’s performance any favours but the only solution would be to try and achieve whatever you have created with one builder, using the other.
VC can usually create most things, assuming they are not very bespoke or custom made for the theme.
- if I understood you right on the sidebars then you effectively want to have a combination of the default widgets and other widgets on pages?
You won’t be able to have two sidebars from different sources on the same page, plus styling is likely to be different.
Again the only way to fix this is to find/use a singular solution