iMac to iPad

1. Depends on how you store your files. If you use iCloud, you can access your files by logging in to your Apple ID at https://icloud.com through a web browser and see your files in he iCloud Drive app there. Mac apps would not be accessible and could not run on an iPad even if they were accessible.
2. You do not want to sign in with your Apple ID on his iPad because that would involve signing him out and it would merge all the data and files from his account into yours.
3. You could potentially install a remote desktop application such as Teamviewer on your Mac and access your Mac through the iPad remotely via the Teamviewer app. It may not be the best experience though.
   1. https://apps.apple.com/us/app/teamviewer-remote-control/id692035811?platform=ipad

Possibly IF your husband only uses iCloud storage . As to whether an iMac or laptop is best that ALWAYS comes down to portability. Do you need it or not????