Ballymore is planned to be used for hockey at the Olympics. Maybe something has already been announced, if so I missed it, but I imagine the stadium will cater for about 10k spectators for this. After that it will go back to QRU presumably, but won't be used for any big rugby games.

Austadiums has renderings of the new McLean Stand at Ballymore.

Demolition of the stand is complete.

https://www.austadiums.com/news/914/ballymore-redevelopment-set-to-kick-off

This makes sense.

the plans for Ballymore is for a 12k matchday crowd but only 3k seats in the new mclean stand with the rest demolished. The latest renders though show them keeping the Eastern stand which would give about 13-15k seats, but i don't think the eastern stand will survive 10 years as it was pretty dilapidated 10 years ago. For the Olympics i think they are planning on 15k seats on the main field using temporary stands on 3 sides and 5k on field 2 (all temporary stands). 

if they end up keeping the eastern stand and giving it a significant upgrade for the olympics it probably would be a suitable sized stadium for the roar however it still has access problems. for the olympics i suspect they will just pump out the busses for spectators with minor upgrades to the roads in and out (and temporary bans on street parking) as well as use temporary pedestrian paths to windsor station for trains. this will likely be an acceptable inconvenience for 2 weeks for the residents in the area but would absolutely not be accepted for regular events.

Do you know what the plans are for the second pitch that is needed?

ballymore already has a second (and third pitch). the old renderings had the third pitch (behind the mclean stand) change positions slightly with offices and parking levels surrounding one end and the side opposite the mclean stand. this is gone in the new renderings so i think may not happen. 

I suspect for the olympics that field 3 will be a warm up pitch (with or without the parking and offices) and they will put temporary stands along both sides of the old xxxx hill. they say 5k of temporary stands for field 2.

Brisbane's 2032 Olympic Games venues will be a mix of new and old. Here's how it will look

https://www.abc.net.au/news/2021-07-22/qld-brisbane-olympic-infrastructure-2032-games/100311674

The 2032 Olympics will catapult south-east Queensland onto the world stage, but there's a long way to go before the region will be ready to meet the demands of hosting the Games.Organisers have pitched the sporting spectacle as a more sustainable and cost-effective event that will leave a meaningful legacy for the growing region.Over the next 11 years, authorities will pour major resources and money into transforming Brisbane into a new world city — though the full cost is still unclear.

Utilising venues new and old

The 2032 Olympic master plan includes three main hubs in the state's south-east corner, which will host 28 sports split across them.There will be 21 venues in Brisbane, seven on the Gold Coast and four on the Sunshine Coast.Football preliminary matches will also be played in Cairns, Townsville, Toowoomba, Sydney and Melbourne.

It's an abomination that football will have brought four major events to Queensland in the 21st century (2000 Olympics, 2015 AC, 2023 WWC, 2032 Olympics),* and still have not a cent spent on a football-specific venue in Brisbane suitable for a professional-level club. Instead the Gabba gets completely rebuilt twice over, and the state throws cash at AFL training grounds or venues that the NRL might consider playing a one-off game in every now and again. Cameron Atfield's idea of redeveloping Perry Park into a 15k-seater football venue, and using it for the Olympic hockey tournament, is infinitely superior to the Ballymore plan: Perry Park has much better transport links, and it would leave a much better legacy than shipping temporary stands into a rugby training ground (and no chance of a white elephant since the Roar and the Strikers would play there, and it could be used for state finals, low-level international fixtures, etc.). But no, that would make too much sense.

The upside is this government intransigence should prompt the Roar to go it alone and build a stadium with private cash. With modular set-ups they can do so cheaply if they find the land (or come to an agreement to use Perry Park), and they would then control all cash-flows: stadium sponsorship, concessions, corporate boxes, etc., while not having to deal with SQ's exorbitant rental fees. It could potentially change the business model of how football clubs operate in this country, and provide a template for clubs in need of better stadium solutions like Wellington, Melbourne City, perhaps even the Jets (leaving the Western United situation to one side for the moment).

* Contrast that with the other major codes: Rugby, 1 World Cup in 2003; Cricket, 1 World Cup in 2015 (with a grand total of two group matches), Rugby League, nothing; AFL, nothing.

Can you fit the required 10,000 seat Hockey stadium and a 5,000 seat Hockey stadium on Perry Park grounds?

Yes, there is a second field to the east of the main field in Perry Park. It'd be a tight squeeze but since hockey fields are somewhat smaller than football fields, not impossible with some temporary stands. It would mean different plans to the ones put out by the Strikers when they made their A-League bid, but it's feasible..