New switch and lights

In a downstairs room (not bathroom or shower room), I want to change a pull switch to a standard light switch and pendant light to spots in different positions to original pendant.

I can reach the switch positions from above by lifting floorboards, but the pendant is out of working reach due to bathroom fittings (can see and feed cables to/from it, though).

For the switch, can I simply extend cables from ceiling pull switch to new switch position using a connector or junction box? If so, what should I use to join cables? Or do (should!) I run new cable to/from pendant (of which, more below)

What should I use to join cables at pendant position? I don’t think I can reach it under floorboards. Planning on using cladding for ceiling, so possible to make larger hole in ceiling if junction box required and push JB above ceiling. Which JB would you recommend?

Alternative might be for me to extend feed from fusebox at the pendant position to a JB in a position I can reach, thereby only extending one cable and not the several which are running from the pendant to other light circuits. Again, what should I use at pendant position, bearing in mind I can only reach from below.

If the junction is going to be buried it will not be accessible, so it will need to be what is known as “maintenance free”

something like this or this

Thanks.

Any thoughts on the cable for the switch? If accessible (by lifting floorboards), can I extend down to new switch position? Simple connector block or something more substantial?

Under floorboards is not accessible!

Use maintenance free connector as described above.

Thanks again!