The aperture you use depends on the result you want. Some people want a shallow depth of field, some what everything in focus.
Do whatever works for you.
Having lots of lights and reflectors can be really useful, but they are not essential. Again, it depends on what you are trying to create. If you are in a studio, having lots of lights is straightforward, but if you are doing things outside it isn't.
Not everyone has assistants. Ignore anyone who says they are necessary.
Having a heavy camera is not essential, and being a DSLR does not make a camera heavier. There are some very light DSLRs out there and some very heavy mirrorless cameras.
This sounds like a person very set in his ways and experienced in only one particular field.
This sounds like a person very set in his ways and experienced in only one particular field.