That a connection stays open for seconds, or minutes, even when no traffic is passing is not just normal, it is the rule. The reason for this delay is that it takes too long to set up a new connection, especially encrypted ones, so connections are usually reused whenever practical (and newer versions of HTTP are designed to not just reuse connections but parallelize requests and responses). The server will usually control how long it will allow an idle connection to remain open, since such connections do use scarce resources on the server; the client may also close them if it has too many open connections.
Vivaldi will, as documented in the article mentioned by Pathduck, immediately after first run, download a number of components from Google, such as the component needed to watch DRM protected videos at Netfix, Amazon Prime, Hulu, and so on, and some that are security information, such as SSL certificate revocation and trust information. Vivaldi will also regularly check for updates for these components, and download other security information, such as Safe Browsing information, if necessary, when you navigate. These requests generally do not enable cookies.
The Google telemetry uploads and trials checks are completely disabled in Vivaldi's code.
Vivaldi will also ping our stats counter once a day, which counts how many users we have; the information transmitted contain no identifying information. This is documented in another of our technical articles.
Please note that there are other background requests that may be sent, that are not Vivaldi-related. Extensions you have installed may request updates from their developer, notification scripts you have permitted from websites will regularly check for updates (either via Google or another service), RSS-feeds and email accounts will regularly do so, as will many panels. I suspect both of your first IP addresses fall into these categories, since one one them in an Amazon cloud IP (which neither we nor Google uses), the other is from an unknown domain. (the three later ones are Google servers, probably components and safe browsing mirrors).
