DIY Budget Patio questions

Hi everyone. It will be my first attempt at any kind of landscaping so excuse me if any of the questions are stupid. So here is the background & plan:

I am planning on extending a path leading to the lawn part of the garden to make a small patio (extending the path by 3.15m x 1.8m). The path is 7 slabs (450mmx450mm) long. The part where I want to extend into is currently filled with some decorative stones and extends to the fence. I believe I need 28 slabs to fill this area.

I want to lay 75mm of MOT type 1 sub-base as according to my calculations this should use up only one bulk bag. The sub-base would go onto a weed membrane. The first question is, is this enough for a light-use, and can I use a 10" hand tamper to compact the base? I already own one and this would save me money on renting a wacker plate.

I am then thinking of laying slabs straight onto that on approx 30mm mortar bed 5:1 ratio of sharp sand to cement. The second question is, are there any cheap alternatives to wheelbarrows? Would plasterers flexitub do? What else I could use to mix the mortar? I am not planning on any more projects that would require a wheelbarrow in the nearest future and storing it would be a hassle.

Third question, do I need edging to support the slabs or will they be fine on the mortar bed? I was thinking of laying simple concrete 15x5x60 cm edging along the edge of the fence and lawn, but If I can get away without it, then I definitely will as it is another £.

The last question is, does the sub-base need to be perfectly level and have no low/high spots at all? My thinking is that the mortar bed would compensate for them if they are slight and will fill the voids.

Thank you for your answers.