There was a time when those sealants were more of a novelty that garages would refuse to repair a puncture if the sealant had been used. Now that most cars have it as standard, has that attitude changed? My Corsa has a pump and a container of sealant in the back, no spare or jack until I bought them, and I have managed to get hold of two identical alloys which are rare as hens teeth. Next door but one has a Corsa with exactly the same design alloys, but mine have five bolts, not the common four.
The 80 sticker on a full size spare wheel marked 88H is a joke, take it off and bin it, H tyres are rated to 130mph, and would only be illegal if the car can reach a higher speed. And citing the 70mph limit would not prevent prosecution. As for different makes mixed up on cars, it is only a recommendation that they match, not law. That said, it would be unwise to mix summer and winter tyres. Check out 90% of older cars running today will not have matching tyres.