Only replace what is damaged... or not reusable ( eg nyloc nuts, spring washers )
Tip, when you take it apart, do it one part at a time and get a load of sealable plastic bags, as you take bits off put them in a bag and label them. This way it makes it a lot easier to put things back together... Even I do this when pulling engines apart, ok I don't need to label them, but when you come back to put a water pump back on, it's so convenient to have the 4 bolts in a bag. It's also a sense check at the end, you should have a load of empty bags.
I figured this would be the easier option and have already taken the engine out now and dismantled it. I have done exactley as you've said already and bagged and tagged so to speak... great minds think alike and all that jazz

this all started as I bought my mini 1990 racing green last year as my learner car and (fingers crossed) car for life! I was only trying to get it through the MOT, get my licence and then was going to take it off the road and rebuild but found a multitude of problems with the wiring and, of course I thought why not just do it now and sort a new wiring loom (I would have tried to salvage it but there is a long brown, constant live wire that has melted throughout the enire length of loom in the engine bay and caused damage to most of the other wires). While I'm waiting on that to be delivered (4 weeks) I decided to sort the rest of the car out as rust is limited (already sorted most of it last year) it's mainly down to the mechanics and electrics of course

Decided to go for a 'classic' look, cream leather interior with british racing green pipping and vertical stitching, walnut centre speedo gauge (smiths of course) and will be fitting mk1 bumpers and over riders to it too. The list is endless, shame the cash isn't lol but will get there enventually. Strong believer in the phrase 'take care of your car and it'll take care of you'