best way to move Home folder

It's best not to move your home folder. This is an especially 'sensitive' part of your system and the architecture of macOS continues to evolve.

If you do not want to store user data in your Home folder then just use your external SSD as a data drive. You can also point Photos, Music, TV and other apps directly to folders on your external SSD; there is no need to symlink from the default folders in your user Home.

Regarding your specific questions -

1 - No. If you move your Home folder and your external SSD is not available (or not available in time) when you boot, your Mac may not actually boot.

2 - Yes, but see my response to #1

3 - There is no guarantee that your symlinks will work on Ventura or any future releases of macOS; and they could be broken, removed or disabled by a macOS update at any time.

4 - No

I concur with @MartinR that it is a bad idea to move the home folder to another location. macOS these days does not like to deviate too far from system defaults. When Monterey was the current OS, a Monterey update patch broke people's custom setups where the home folder was on another volume. This happened with several different Monterey update patches & I believe it may have occurred when people upgraded to Ventura as well.

I haven't seen any recent reports that any Ventura updates have broken such a setup, but it is something that a user needs to consider....is it worth the risk? Can you afford the time & effort to figure out how to fix it if the setup does break? I know that resolving the issue was not quite as straight forward as you would expect since macOS created a new home folder on the boot drive (user lost admin permissions). If you choose this option, make sure to keep the old home folder on the boot drive and to keep a second spare admin user account available.

I've also seen reports where people encountered issues when restoring from their Time Machine backup with these setups....even if the home folder is reverted back to the boot drive. Like I mentioned, macOS does not like surprises or deviating too far from system defaults.

I do know Apple has some official instruction in Apple articles for placing Photos & Music to another volume, so that may be a "safe" option, but I also know that Apple has decided to change it mind on things so the next version of macOS may no longer support it (even a simple update patch to the current OS could remove support since no one really respects the major & minor versioning these days where system feature changes should only occur with major OS/app revisions).