New player help

Have a Rogal Dorn and a Baneblade.

Plan to get old CB, a leman russ and 30k Solar auxilia CB. Convert the latter with bits from CB cadians and sponsons from 40k russ.

Then once painted one more 40k and 30k russ. Or maybe just repeat the above if i still can get old cb.

I am a lore Timmy and hobbyist first so want model and visual variety.

Does my plan work? Am i missing something? Will these minis work on flgs tournaments?