Hi there ,
I have one Linnie male (his partner passed away a few months ago ) .
Compared to budgies , they are very mellow and easy going. They seem to prefer climbing and flying over walking and make little to no noise at all.
My little male loves having baths everyday.
Regarding nails , yes they do grow really fast. I do a small trimming every month. But I also place rough perches in strategic areas of the cage to wear the nails down.
Regarding housing with budgies , my linnie male (Pluto) is completely bonded to my female budgie (Saturn) and live together in a cage separately from the rest of my flock.
The fact that he lost his mate and that my budgie was new and just out quarantine played a role in forming their bond.
My female just moved into his cage one day when I left it open. Since then they've been inseparable. They pine for each other when separated , eat , drink and sleep together as well.