Amhlaidgh Please treat the following with a degree of caution as this is all from memory and relates more to C15th, and then primarily England, than C14th Scotland but hopefully it'll provide a starting point.
The question which is most important to answer before anything else is your question 1. Unless you have made a decision on what social position and income your portrayal has question 2. is impossible to answer in anything other than the most horrendously general terms.
Later Scottish Acts of parliament (probably earlier too but I only have ones from about 1420 on) detail the equipment required for a man to appear at a 'weapon showing' according to their income, this was a common approach to the the differing responsibilities towards service. The more money you had (whether from landed income or moveable income) the better the level of equipment. This closely mirrors much Sumptuary legistation which focuses on your degree (both in terms of nobility and in terms of wealth).
So to know what would be 'expected' and considered 'the social norm' you need to know your place in society ... both to know the military equipment you should have and the type of clothes.
I'm not suggesting Sumptuary Legislation was rigidly enforced, far from it and Scottish womens excess in headcoverings were noted in the C15th, but if you want to be 'normal' or a 'regular guy' as you suggest then start there.
With this in mind ... the type of clothes will be directly related to your social standing. The quality of cloth, the colours used all relate directly to social position, your degree.
For the C14th I think that you would be looking more towards the twill cloths than broadcloth in Scotland, though the Museum of London's (MOL) book on textiles from the excavations in London gives a good overview of these shifts in the type of fabrics used. Twill cloths are traditionally not fulled (i.e. they don't have the nap raised & shorn to give the slightly fluffy surface which hides the weave) and are often patterned weave. So I'd actually say that fulled cloth shouldn't necessarily be your priority, though if you want to get a reasonable modern 'broadcloth' equivilant fabrics such as melton are a reasonable starting point.
The colours available and the colours used is a tricky subject for which archaeology gives only limited (but vital) evidence. In essence there are three main dyes ... there are a myriad of others but these are almost invariabley either a) too costly or b) not used commercially. Most cloth was mass produced and sold ready dyed, even cheap cloths. Some homespun/homedyed stuff invariably existed but if you want to keep to the average ... the mass produced cloth in the commercial dye colours is the place to work from.
These dyes are woad (blue) weld (yellow) and madder (red). When used in combination (or with other 'secret ingredients' that a specifric dyer might use to get a specific hue) then just about any colour is possible, but the core colours appear to have been : reds, blues, greens, greys (actually probably a blue grey as it is also madder based) and cheap blacks using oak gall ... not a 'pure' black as kit rapidly decays to a green/brown black.
Scotland was famous later (not sure when it started though) for blue dyed caps and the dark colour initially required for the backing to the national badge (the white saltaire) became established as blue (it's probably the cheapest colour ... undyed white (blanket) being cheaper.
These are the sorts of colours discussed in an Act of Apparrel (sumptuary law) from Scotland for the common folk.
As regards detail of the clothing ... late 14th is not my area, I'd have to look it up I'm afraid but I thought the later C14th was 'the' period for cloth buttons (remember these are slightly different to modern buttons as they attach to the edge of the cloth via a stalk, not through the centre of the button head.
Finally to the armour ... either decide on the wealth of your man and I'll dig out the equipment for a later soldier for comparsison ... or say what you want/have and I'll tell you as best I can what social ranking you would have to have to have this equipment.
Hope that helps.
Cheers
Dave