Me too - paranoia that is. I back up to a Time Capsule which, as you say, I would like to hide in the loft or a wall void somewhere. I also periodically back up to an external drive which I keep separate from the computer.
Time machine will allow you to keep backups on several drives concurrently. The only cloud backup I use is my apple mail, contacts, calendar and notes but you can use more - eg photos and documents. Wherever you back up, it is usually only the first backup that takes some time, thereafter it is only the changes that need to be backed up. Time machine keeps adding backups until the drive is full and then deletes the oldest ones to make way for newer ones.
I don't use any anti-virus software but I occasionally scan with a malware checker. I use MS Office, through and annual subscription, which gives 5 installs of the latest versions of either Office for Windows or for Mac, or both, and can also be be used on tablets in addition to the 5 'PC' installations. I use OSX on a Macbook as my main computer but have windows installed in bootcamp on my iMac so that can boot up in either OSX (although it is too old to run the latest version) or windows. I have MS Office running on both partitions.
The main reason I have the windows partition is for some work I was doing using Office. The company reckoned there were odd differences, deep in the formatting, between documents and presentations written in office for mac versus those composed in the windows version.