those routes are definitely compatible and quite spectacular. I walked this combination last year and loved it.
for the podiensis - norte link, there are several options, most of them outlined in the posts above.
I walked it lake this, following gr-10 most of the way:
https://www.wikiloc.com/hiking-trai...ed-de-port-saint-etienne-de-baigorry-17988679
a short day in preparation for the big day tommorrow. this is gr-10 with a combination of other routes and roads because I wanted to cut out the climb and descent of the mountain (I can't remember the name at the moment).
https://www.wikiloc.com/hiking-trails/camino2016-045-saint-etienne-de-baigorry-bidarray-17989159
a spectacular day, worth every sweat. a steep but good climb of almost 1000m of altitude difference, then following a ridge, and a steep and stony descent for about the same altitude difference. the ridge is by no means flat, there is one very short section where a scramble is necessary, leading down the the lowest saddle where there is the only water on the route - a small source that is usually at least trickling. the view all along spectacular. did you know that pic d'iparla is the highest summit in both basque countries? I didn't. I heard there is an alternative to the steep stony descent, but the first part is unmarked and you probably need to meet someone who knows it. gite d'etape for solo travellers is the one at the far end of the village, but it has a fine view of the half of the day's route. I got a single room. there's a kitchen. don't miss the interesting church.
definitely not recommended in bad weather, rain or snow. in this case, chemin de la nive follows a small road along the valley to the east of the ridge all the way to bidarray. this also saves a day of walking.
https://fr.wikiloc.com/itineraires-randonnee/camino2016-046-bidarray-ainhoa-17989675
the tricky part of the day is the climb to col d'artzatey which should be avoided if wet. part of the route is very eroded (it was being reparied in 2016), there are iron rails, and part is very exposed. I didn't feel uneasy at any time, but some might. if that is that case, there is an alternative chemin de contrebandiers (or sth like that) that follows a forest road to col de méhatché. the rest is beautiful and if you have enough energy, you can even extend the day to sare (but gite d'etape there is quite a way out of the town). gite d'etape ok, with kitchen.
https://fr.wikiloc.com/itineraires-randonnee/camino2016-047-ainhoa-olhette-17990191
the first part to sare no problems at all. then a climb to la rhune, which is mostly ok, just a short section is very stony and probably unpleasant if wet. when crossing the wide saddle, pay attentions to waymarks, as may routes and paths intersect here. the descent is a bit long. manttu baita is no longer a gite d'etape. the new chambres d'hotes - gite d'etape is just before the main road in olhette, trapero baita. there are two small rooms with very wide bunks and a swimming pool. half-pension only.
https://fr.wikiloc.com/itineraires-randonnee/camino2016-048-olhette-irun-17990592
this was a rainy day, so I completely avoided gr-10 and cobbled together sth from local roads, lanes and paths. I am not sure if the lane at 5.8km is public or private, I encountered a fox hunt there, but I had no problems passing by.
gite d'etape in hendaye closed in 2016. youth hostel in irun was also closed for renovation. but albergue de peregrinos in irun is very nice. there is also albergue juvenil at the other end of hondaretta, with a route signposted directly up to ermita de guadalupe.