Abuse? Come on Al.
Welcome to our forum Peter C.
You have a very nice looking tank there. Don't worry too much about heater orientation. It is common to place it at an angle to make the adjustment knob easy to reach while getting it to lay down some, but the way you have it will work fine too. If your tank is less than about 40cm tall, angels would not be such a good idea but I have no idea the actual measurements of your tank. It may be just fine for angels for all that I know.
Since you have your parents tanks to draw from, I would do a filter clone rather than a typical filter cycle. What I do is to get everything up and running in a new tank, then I use that tank as a cleaning bucket for one of my established filters. The end result is a bit of an eye sore but a filter with a good seeding of the right bacteria. After that I treat it more or less like a fishless cycle by dosing some ammonia each day and verify that there is no build up of ammonia or nitrites. By the end of the week I am doing a massive water change and tank cleaning so that I can go shopping for fish.