The minute a country enters into a trade agreement with another country it surrenders some of its sovereignty. The 'rules' of the the agreement are arrived at by negotiation and mutual agreement and usually involve both sides accepting compromises which might not be entirely to their liking. In the case of dispute there has to be an arbitrator. This is the function of the ECJ, if member states break the 'rules' which they have signed up to as members of the EU (and have been instrumental in making subsequent ones by virtue of their membership) the ECJ considers the evidence, makes a judgement and proposes a penalty.
The WTO has its equivalent so leaving the EU does not absolve the UK from having to observe rules of trade. It just answers to a different arbitrator.
for a greater part of your list, POGS I could possibly refer you to this House Of commons Library research paper:
How much legislation comes from Europe?
For me these passages from the summary (which may be all you care to read) are quite telling:
It is difficult to differentiate between EU-induced and nationally induced changes to the law. Governments might have intended to implement legislation in areas in which the EU decides to act, or have legislated in anticipation of the adoption of an EU law. These do not then show up as EU-based, even though they might have been EU influenced. In addition, if calculations focus on politically defined sectors, they may vary over time and across Member States. What is meant by ‘economics’ in one State, for example, may differ from what is called ‘economics’ in another.
Figures don’t give an insight into relative importance or salience of EU or national legislative acts. For example, the UK’s European Communities (Finance) Act 2001 to adopt the Council Decision on the EU’s system of own resources was more significant in terms of its impact than, for example, the Olympic Symbol etc (Protection) Act 1995. Figures don’t give information on how EU laws affect the daily lives of citizens or businesses - the relative material impact. For example, the ‘working time directive’ is arguably of far greater significance to the working population of the Member States than, for example, the Commission Regulation on “the classification of padded waistcoats in the Combined Nomenclature”.
researchbriefings.files.parliament.uk/documents/RP10-62/RP10-62.pdf
And to this EU summary of The Balance of Competences Review in the United Kingdom, 2012-2014
(which I have linked to because it is clear, appears to be objective and is comprehensive, not because it is an EU production)
www.europarl.europa.eu/RegData/etudes/BRIE/2016/573915/EPRS_BRI(2016)573915_EN.pdf
At least one commentary on the report concludes: It felt the review showed no convincing case for transferring competences back from the EU to the UK in any of the policy areas considered.
As this was the Senior European Experts group, a body consisting largely of retired high-ranking British diplomats and civil servants, it may be regarded as either highly suspect or worthy of respect, depending on your view of expertise and experience at international level.
With regard to the Charter of Fundamental Rights I would say that I see nothing wrong in the the explicit codification of rights for the avoidance of doubt and that as we are already signed up to the European Convention on Human Rights, a much earlier initiative which the UK was instrumental in driving, and which is entirely separate from the EU, I really cannot get particularly excercised in any way by the EU having one as well.
I'd note that the two are frequently confused and that even our PM didn't seem to recognise that the European Court of Human Rights (ECHR) and the European Court of Justice (ECJ) are two completely different and distinct entities and the the ECHR has nothing at all to do with the EU, when she declared early in her premiership that we were going to withdraw from the ECHR. Haven't heard much about that of late. One hopes she quickly realised her error. To withdraw from the ECHR would indeed paint the UK in a dreadful light.