I would go for a meter that has K-Type thermocouple reading (ADM02 is the one I like and sell out of the cheap chinese meters, fuses on both ranges, backlight, auto off, temperature)
0.3mm solder is a bit small for my liking, especially with marginal flux content chinese stuff. 0.6-0.8 probably better. But that said I'm currently using a spool of "Best" brand 0.4mm which is fairly decent.
Flux pen... matter of preference perhaps, but I use syringe paste flux (knock off Amtech brand all over the usual pkaces).
Magnifier and microscope... I'd put those at the end of the list, if your vision is any good somebody who is "setting up an electronics lab" is probably not at the level where they are going to be using components small enough to need magnification beyond a magnifying glass from the local $2 shop.
I would take the money from the magnification stuff and put it towards a hot air station first (perhaps instead of the iron suggested, get one with hot air as well), far more essential and useful if dealing with surface mount, and even beginners are going to deal with surface mount (and should, because it's easier) - or at the very least, for shrinking heatshrink.
I would also try and squeeze out another $5 for a cheap 8ch logic analyzer, and use it with sigrok open source logic analyzer software. I get more use out of the LA than out of a scope, being digitally minded.