How many visior to level 120 a unit and 99 a vision card ?

Depends how much you spend on summoning. After that 0 visior. Barrack it all the way :).

If the vision card is limited its 12.000 visiore if the vision card is not limited its 9.000 visiore if unit limited 60.000 visiore if not limited 15.000

chocobo expeditions can also drop shards. Not reliably, but it's extra shards here and there which adds up eventually.

Very rough way to calculate is basically 1 unit shard costs 50 visiore since 40 shards are being sold for 2000 visiore in the shop. This means you need a total of 50k visiore, assuming it's visiore only, and 13,750 for VC.

But realistically, it's cheaper because you can slow build them through guild barracks and daily shard quests, as well as saved up stars.

Newly released unit/vcs are also cheaper/faster to build because of daily gil banners, access to the bingo board, and summoning on their banner gives extra currency that can be exchanged for shards.