I think one of the problems is that people mostly get their information from the media, including me, and the media only seem able to deal in 10 second sound bites. The information, therefore, tends to be quite simplistic. Take for an example the automotive sector. It is presented as "It isn't in the interest of the EU or the UK to impose tariffs since Mercedes and BMW will still want to sell cars in the UK as much as the UK wants to sell them in the EU." This implies that the situation is symmetric but it very much isn't.
About two thirds of the components used to build a car in the UK are imported from the EU. Suppose a 10 % tariff was imposed on everything in the automotive sector crossing from the EU into the UK and from the UK into the EU. All those components would be subject to the 10 % tariff when they enter the UK. Obviously that isn't going to add 10 % to the cost of a car inside the UK but it will increase it. Exactly how much I don't know but let's say 5 %. When that car is exported to the EU it will also face a 10 % tariff so, in total it will be 15 % more expensive than it was before the tariffs were imposed. The cost of cars produced in the EU by Mercedes, BMW, Seat, Peugeot, Citroen etc will not have increased at all so it is going to be more difficult for UK export cars to compete with EU produced ones. Looking at it the other way the EU produced cars will also be subject to the 10 % tariff when they enter the UK but the locally produced cars will have also gone up by 5 % so the EU produced ones are only 5 % more expensive. Still a barrier but not as big. Even that analysis is over simplistic. Extra paperwork and customs inspections could cause further increases in cost on the incoming components, either directly or indirectly by introducing delays, which transforms into cost in today's JiT manufacturing methodology. That only worsens the asymmetry. The one thing you can say with some certainty is that tariffs always work to the disadvantage of the consumer, i.e. you and me.
I have no idea how much of the recent fall in Sterling is due to Brexit and how much to other economic factors. You can only really look at currency pairs so any changes are a result of what is happening in both countries involved. If you look at the Sterling - Euro pair it was falling before the referendum. It started to level off/recover when it looked like the vote would be to remain. It dropped suddenly back onto its previous downward trajectory once it was known the vote was to leave and continued on that path into October. Since then it has been recovering a bit. Against the US$ it is more like three steps. Flat up to the referendum, a big sudden step down to another flat and then a slower drop to a new flat in October. Obviously throughout that 12 month period things were happening in the EU and in the USA so what caused the moves, Brexit, Trump, Italian banking problems etc etc.? You can also look over the much longer term
which tends to suggest that Sterling is in a long term decline against the dollar with periods of stability and/or respite.
Every country in the world wants to depress their currency to improve competitiveness. Obviously that can't happen since one country's up is another country's down. Every country in the world wants to get inflation increasing because it is the only solution to their debt problems, i.e. inflate away the value. All these actions have other consequences, however, and many can be very unpleasant. When inflation starts it has a habit of running away and it is then extremely difficult to stop. If central banks start to raise interest rates to slow inflation what happens to those in debt who now cannot afford their repayments? What happens to the companies who have taken on massive corporate debt to implement share buy back schemes who find that when they need to roll over their bonds the rate has tripled or quadrupled. They haven't invested the debt to increase income so where do they get the money to make the higher repayments? If companies start to default on their corporate bonds how long before we have a repeat of the sub-prime crisis with financial institutions like pension companies suddenly finding that the CDOs they have bought are worthless? There are plenty of bear traps out there apart from Brexit.
Overall I go along with the "nothing has happened yet" viewpoint. When article 50 is triggered it shouldn't be long before we know what the EU's negotiating position is and, depending on what it is, that could provoke changes that are clearly attributable to Brexit.